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1.
Sci Signal ; 16(792): eabn8668, 2023 07 04.
Article in English | MEDLINE | ID: mdl-37402225

ABSTRACT

Receptor-type protein phosphatase α (RPTPα) promotes fibroblast-dependent arthritis and fibrosis, in part, by enhancing the activation of the kinase SRC. Synovial fibroblasts lining joint tissue mediate inflammation and tissue damage, and their infiltration into adjacent tissues promotes disease progression. RPTPα includes an ectodomain and two intracellular catalytic domains (D1 and D2) and, in cancer cells, undergoes inhibitory homodimerization, which is dependent on a D1 wedge motif. Through single-molecule localization and labeled molecule interaction microscopy of migrating synovial fibroblasts, we investigated the role of RPTPα dimerization in the activation of SRC, the migration of synovial fibroblasts, and joint damage in a mouse model of arthritis. RPTPα clustered with other RPTPα and with SRC molecules in the context of actin-rich structures. A known dimerization-impairing mutation in the wedge motif (P210L/P211L) and the deletion of the D2 domain reduced RPTPα-RPTPα clustering; however, it also unexpectedly reduced RPTPα-SRC association. The same mutations also reduced recruitment of RPTPα to actin-rich structures and inhibited SRC activation and cellular migration. An antibody against the RPTPα ectodomain that prevented the clustering of RPTPα also inhibited RPTPα-SRC association and SRC activation and attenuated fibroblast migration and joint damage in arthritic mice. A catalytically inactivating RPTPα-C469S mutation protected mice from arthritis and reduced SRC activation in synovial fibroblasts. We conclude that RPTPα clustering retains it to actin-rich structures to promote SRC-mediated fibroblast migration and can be modulated through the extracellular domain.


Subject(s)
Actins , Arthritis , Animals , Mice , Cluster Analysis , Fibroblasts/metabolism , Phosphoprotein Phosphatases , Protein Tyrosine Phosphatases/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism
2.
PLoS One ; 17(7): e0271499, 2022.
Article in English | MEDLINE | ID: mdl-35900966

ABSTRACT

The genetic study of multi-incident families is a powerful tool to investigate genetic contributions to the development of Parkinson's disease. In this study, we identified the rare PTPRA p.R223W variant as one of three putative genetic factors potentially contributing to disease in an Australian family with incomplete penetrance. Whole exome sequencing identified these mutations in three affected cousins. The rare PTPRA missense variant was predicted to be damaging and was absent from 3,842 alleles from PD cases. Overexpression of the wild-type RPTPα and R223W mutant in HEK293T cells identified that the R223W mutation did not impair RPTPα expression levels or alter its trafficking to the plasma membrane. The R223W mutation did alter proteolytic processing of RPTPα, resulting in the accumulation of a cleavage product. The mutation also resulted in decreased activation of Src family kinases. The functional consequences of this variant, either alone or in concert with the other identified genetic variants, highlights that even minor changes in normal cellular function may increase the risk of developing PD.


Subject(s)
Parkinson Disease , Australia , Genetic Predisposition to Disease , HEK293 Cells , Humans , Mutation , Parkinson Disease/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Exome Sequencing
3.
Proc Natl Acad Sci U S A ; 118(47)2021 11 23.
Article in English | MEDLINE | ID: mdl-34782459

ABSTRACT

Although there have been many studies of gene variant association with different stages of HIV/AIDS progression in United States and European cohorts, few gene-association studies have assessed genic determinants in sub-Saharan African populations, which have the highest density of HIV infections worldwide. We carried out genome-wide association studies on 766 study participants at risk for HIV-1 subtype C (HIV-1C) infection in Botswana. Three gene associations (AP3B1, PTPRA, and NEO1) were shown to have significant association with HIV-1C acquisition. Each gene association was replicated within Botswana or in the United States-African American or United States-European American AIDS cohorts or in both. Each associated gene has a prior reported influence on HIV/AIDS pathogenesis. Thirteen previously discovered AIDS restriction genes were further replicated in the Botswana cohorts, extending our confidence in these prior AIDS restriction gene reports. This work presents an early step toward the identification of genetic variants associated with and affecting HIV acquisition or AIDS progression in the understudied HIV-1C afflicted Botswana population.


Subject(s)
Genetic Variation , Genome-Wide Association Study , HIV Infections/genetics , Acquired Immunodeficiency Syndrome , Adaptor Protein Complex 3/genetics , Adaptor Protein Complex beta Subunits/genetics , Botswana/epidemiology , Genotype , HIV Infections/epidemiology , Humans , Nerve Tissue Proteins/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Receptors, Cell Surface/genetics
4.
Mol Cancer ; 20(1): 68, 2021 04 14.
Article in English | MEDLINE | ID: mdl-33853613

ABSTRACT

BACKGROUND: Circular RNAs (circRNAs) have been found to have significant impacts on bladder cancer (BC) progression through various mechanisms. In this study, we aimed to identify novel circRNAs that regulate the function of IGF2BP1, a key m6A reader, and explore the regulatory mechanisms and clinical significances in BC. METHODS: Firstly, the clinical role of IGF2BP1 in BC was studied. Then, RNA immunoprecipitation sequencing (RIP-seq) analysis was performed to identify the circRNAs interacted with IGF2BP1 in BC cells. The overall biological roles of IGF2BP1 and the candidate circPTPRA were investigated in both BC cell lines and animal xenograft studies. Subsequently, we evaluated the regulation effects of circPTPRA on IGF2BP1 and screened out its target genes through RNA sequencing. Finally, we explored the underlying molecular mechanisms that circPTPRA might act as a blocker in recognition of m6A. RESULTS: We demonstrated that IGF2BP1 was predominantly binded with circPTPRA in the cytoplasm in BC cells. Ectopic expression of circPTPRA abolished the promotion of cell proliferation, migration and invasion of BC cells induced by IGF2BP1. Importantly, circPTPRA downregulated IGF2BP1-regulation of MYC and FSCN1 expression via interacting with IGF2BP1. Moreover, the recognition of m6A-modified RNAs mediated by IGF2BP1 was partly disturbed by circPTPRA through its interaction with KH domains of IGF2BP1. CONCLUSIONS: This study identifies exonic circular circPTPRA as a new tumor suppressor that inhibits cancer progression through endogenous blocking the recognition of IGF2BP1 to m6A-modified RNAs, indicating that circPTPRA may serve as an exploitable therapeutic target for patients with BC.


Subject(s)
Adenosine/analogs & derivatives , RNA, Circular/genetics , RNA-Binding Proteins/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/metabolism , Adenosine/metabolism , Animals , Cell Cycle/genetics , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Disease Models, Animal , Disease Progression , Epigenesis, Genetic , Fluorescent Antibody Technique , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , Heterografts , Humans , Immunohistochemistry , Mice , Models, Biological , Protein Binding , RNA, Circular/metabolism , Urinary Bladder Neoplasms/mortality , Urinary Bladder Neoplasms/pathology
5.
J Biochem ; 169(2): 187-194, 2021 Mar 05.
Article in English | MEDLINE | ID: mdl-33313879

ABSTRACT

Receptor protein tyrosine phosphatases (RPTPs) are type-I transmembrane proteins and involved in various biological and pathological processes. Their functions are supposed to be exerted through tyrosine dephosphorylation of their specific substrates. However, our comprehensive understanding of specific substrates or interacting proteins for RPTPs is poor. PTPRσ belongs to class 2a RPTP family, dephosphorylates cortactin, and leads to autophagy flux disruption and axonal regeneration inhibition in response to its ligand chondroitin sulphate. Here, we applied proximity-dependent biotin identification (BioID) assay, a proximity-labelling assay, to PTPRσ and reproducibly identified the 99 candidates as interactors for PTPRσ including already-known interactors such as Liprin-α and Trio. Of note, cortactin was also listed up in our assay. Our results suggest that the BioID assay is a powerful and reliable tool to identify RPTP-interacting proteins including its specific substrate.


Subject(s)
Chondroitin Sulfates/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Recombinant Fusion Proteins/metabolism , Autophagy/physiology , Biotinylation/methods , Cell Line , HEK293 Cells , Humans , Phosphorylation , Protein Binding , Protein Interaction Domains and Motifs , Proteomics/methods , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Recombinant Fusion Proteins/genetics
6.
Int J Biochem Cell Biol ; 131: 105908, 2021 02.
Article in English | MEDLINE | ID: mdl-33359015

ABSTRACT

Cells have developed a unique set of molecular mechanisms that allows them to probe mechanical properties of the surrounding environment. These systems are based on deformable primary mechanosensors coupled to tension transmitting proteins and enzymes generating biochemical signals. This modular setup enables to transform a mechanical load into more versatile biochemical information. Src kinase appears to be one of the central components of the mechanotransduction network mediating force-induced signalling across multiple cellular contexts. In tight cooperation with primary sensors and the cytoskeleton, Src functions as an effector molecule necessary for transformation of mechanical stimuli into biochemical outputs executing cellular response and adaptation to mechanical cues.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Crk-Associated Substrate Protein/genetics , Cytoskeleton/metabolism , Mechanotransduction, Cellular/genetics , Neoplasms/metabolism , Transcription Factors/genetics , src-Family Kinases/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , Crk-Associated Substrate Protein/metabolism , Cytoskeleton/pathology , Cytoskeleton/ultrastructure , Extracellular Matrix/metabolism , Extracellular Matrix/pathology , Extracellular Matrix/ultrastructure , Gene Expression Regulation , Hippo Signaling Pathway , Humans , Integrins/genetics , Integrins/metabolism , Neoplasms/genetics , Neoplasms/pathology , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Stress, Mechanical , Transcription Factors/metabolism , YAP-Signaling Proteins , src-Family Kinases/metabolism
7.
Aging (Albany NY) ; 12(24): 24651-24670, 2020 12 22.
Article in English | MEDLINE | ID: mdl-33351778

ABSTRACT

MYC overexpression is a common phenomenon in gastric carcinogenesis. In this study, we identified genes differentially expressed with a downregulated profile in gastric cancer (GC) cell lines with silenced MYC. The TTLL12, CDKN3, CDC16, PTPRA, MZT2B, UBE2T genes were validated using qRT-PCR, western blot and immunohistochemistry in tissues of 213 patients with diffuse and intestinal GC. We identified high levels of TTLL12, MZT2B, CDC16, UBE2T, associated with early and advanced stages, lymph nodes, distant metastases and risk factors such as H. pylori. Our results show that in the diffuse GC the overexpression of CDC16 and UBE2T indicate markers of poor prognosis higher than TTLL12. That is, patients with overexpression of these two genes live less than patients with overexpression of TTLL12. In the intestinal GC, patients who overexpressed CDC16 had a significantly lower survival rate than patients who overexpressed MZT2B and UBE2T, indicating in our data a worse prognostic value of CDC16 compared to the other two genes. PTPRA and CDKN3 proved to be important for assessing tumor progression in the early and advanced stages. In summary, in this study, we identified diagnostic and prognostic biomarkers of GC under the control of MYC, related to the cell cycle and the neoplastic process.


Subject(s)
Adenocarcinoma/genetics , Proto-Oncogene Proteins c-myc/genetics , Stomach Neoplasms/genetics , Adenocarcinoma/metabolism , Adenocarcinoma/mortality , Apc6 Subunit, Anaphase-Promoting Complex-Cyclosome/genetics , Apc6 Subunit, Anaphase-Promoting Complex-Cyclosome/metabolism , Cell Line, Tumor , Cyclin-Dependent Kinase Inhibitor Proteins/genetics , Cyclin-Dependent Kinase Inhibitor Proteins/metabolism , Down-Regulation , Dual-Specificity Phosphatases/genetics , Dual-Specificity Phosphatases/metabolism , Female , Gene Silencing , Humans , Male , Microtubule-Associated Proteins/genetics , Microtubule-Associated Proteins/metabolism , Middle Aged , Peptide Synthases/genetics , Peptide Synthases/metabolism , Prognosis , RNA, Small Interfering , RNA-Seq , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Stomach Neoplasms/metabolism , Stomach Neoplasms/mortality , Ubiquitin-Conjugating Enzymes/genetics , Ubiquitin-Conjugating Enzymes/metabolism
8.
Anticancer Res ; 40(10): 5667-5671, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32988891

ABSTRACT

BACKGROUND: Renal cell carcinoma (RCC) is a common urological cancer, and its risk correlates with environmental factors such as obesity, smoking and hypertension. Microarray technology enables analysis of the expression pattern of the whole phosphatome, members of which are involved in many cellular pathways and may act as either tumour suppressors or oncogenes in cancers. MATERIALS AND METHODS: We analysed data for the expression level of 87 out of 107 known protein phosphatase genes included in the Hugo Gene Nomenclature Committee Website for 72 RCC tissues and paired healthy tissues obtained from the GEO Database. RESULTS: Our analysis revealed overexpression of DUSP1, DUSP4, PTP4A3, PTPRC and PTPRE genes at all examined stages of RCC. Moreover, we found overexpression of PTPN12 at stage 2, overexpression of CDKN3 at stages 3 and 4, and overexpression of DUSP10 and PTPN22 at stages 2, 3 and 4. Lower expression of DUSP9, PTPR9 and PTPRO was also observed at all stages. CONCLUSION: Significant changes in expression patterns of protein tyrosine phosphatase genes confirm the involvement of this group in crucial carcinogenesis pathways underlying RCC. Thus, we postulate that protein tyrosine phosphatases play an important role in RCC promotion and progression, and may be considered as potential therapeutic targets.


Subject(s)
Carcinoma, Renal Cell/genetics , Cell Proliferation/genetics , Oncogenes/genetics , Protein Tyrosine Phosphatases/genetics , Carcinoma, Renal Cell/pathology , Cell Line, Tumor , Cyclin-Dependent Kinase Inhibitor Proteins/genetics , Dual Specificity Phosphatase 1/genetics , Dual-Specificity Phosphatases/genetics , Female , Gene Expression Profiling , Gene Expression Regulation, Neoplastic/genetics , Humans , Leukocyte Common Antigens/genetics , Male , Mitogen-Activated Protein Kinase Phosphatases/genetics , Neoplasm Proteins/genetics , Neoplasm Staging , Receptor-Like Protein Tyrosine Phosphatases, Class 3/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Risk Factors , Signal Transduction/genetics , Smoking/adverse effects
9.
Nat Commun ; 11(1): 169, 2020 01 10.
Article in English | MEDLINE | ID: mdl-31924785

ABSTRACT

Leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs) are cell adhesion molecules involved in mediating neuronal development. The binding of LAR-RPTPs to extracellular ligands induces local clustering of LAR-RPTPs to regulate axon growth and synaptogenesis. LAR-RPTPs interact with synaptic liprin-α proteins via the two cytoplasmic phosphatase domains, D1 and D2. Here we solve the crystal structure of LAR_D1D2 in complex with the SAM repeats of liprin-α3, uncovering a conserved two-site binding mode. Cellular analysis shows that liprin-αs robustly promote clustering of LAR in cells by both the liprin-α/LAR interaction and the oligomerization of liprin-α. Structural analysis reveals a unique homophilic interaction of LAR via the catalytically active D1 domains. Disruption of the D1/D1 interaction diminishes the liprin-α-promoted LAR clustering and increases tyrosine dephosphorylation, demonstrating that the phosphatase activity of LAR is negatively regulated by forming clusters. Additionally, we find that the binding of LAR to liprin-α allosterically regulates the liprin-α/liprin-ß interaction.


Subject(s)
Neurogenesis/physiology , Receptor-Like Protein Tyrosine Phosphatases, Class 4/chemistry , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Animals , Axons/physiology , Binding Sites , COS Cells , Cell Adhesion/physiology , Chlorocebus aethiops , Cluster Analysis , Crystallography, X-Ray , Ligands , Molecular Docking Simulation , Mutagenesis, Site-Directed , Protein Conformation , Protein Interaction Domains and Motifs , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Synapses/metabolism
10.
Sci Adv ; 5(12): eaax9230, 2019 12.
Article in English | MEDLINE | ID: mdl-31844669

ABSTRACT

Long noncoding RNAs (lncRNAs) are important regulators of diverse biological processes; however, their function in macrophage activation is undefined. We describe a new regulatory mechanism, where an unreported lncRNA, PTPRE-AS1, targets receptor-type tyrosine protein phosphatase ε (PTPRE) to regulate macrophage activation. PTPRE-AS1 was selectively expressed in IL-4-stimulated macrophages, and its knockdown promoted M2 macrophage activation via MAPK/ERK 1/2 pathway. In vivo, PTPRE-AS1 deficiency enhanced IL-4-mediated M2 macrophage activation and accelerated pulmonary allergic inflammation while reducing chemical-induced colitis. Mechanistically, PTPRE-AS1 bound WDR5 directly, modulating H3K4me3 of the PTPRE promoter to regulate PTPRE-dependent signaling during M2 macrophage activation. Further, the expression of PTPRE-AS1 and PTPRE was significantly lower in peripheral blood mononuclear cells from patients with allergic asthma. These results provide evidence supporting the importance of PTPRE-AS1 in controlling macrophage function and the potential utility of PTPRE-AS1 as a target for controlling inflammatory diseases.


Subject(s)
Asthma/genetics , Inflammation/genetics , RNA, Long Noncoding/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Animals , Asthma/metabolism , Asthma/pathology , Cell Proliferation/genetics , Disease Models, Animal , Epigenesis, Genetic/genetics , Humans , Inflammation/metabolism , Inflammation/pathology , Interleukin-4/metabolism , Leukocytes, Mononuclear/metabolism , Leukocytes, Mononuclear/pathology , MAP Kinase Signaling System/genetics , Macrophage Activation/genetics , Macrophages/metabolism , Macrophages/pathology , Mice
11.
EBioMedicine ; 44: 182-193, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31160270

ABSTRACT

BACKGROUND: Non-small cell lung carcinomas (NSCLC) are prevalent, lethal cancers with especially grim prospects due to late-stage detection and chemoresistance. Circular RNAs (circRNAs) are non-coding RNAs that participate in tumor development. However, the role of circRNAs in NSCLC is not well known. This study investigated the role of one circRNA - circPTPRA- in NSCLC and characterized its molecular mechanism of action. METHODS: circPTPRA expression was analyzed in human NSCLC tumors and matched healthy lung tissue. We performed functional characterization in NSCLC cell lines and a mouse xenograft model of NSCLC to elucidate the molecular role of circPTPRA in epithelial-mesenchymal transitioning (EMT). We also assessed the regulatory action of circPTPRA on the microRNA miR-96-5p and its target the tumor suppressor Ras association domain-containing protein 8 (RASSF8). FINDINGS: circPTPRA was significantly downregulated in NSCLC tumors relative to matched healthy lung tissue. Lower circPTPRA levels correlated with metastasis and inferior survival outcomes in NSCLC patients. circPTPRA suppressed EMT in NSCLC cell lines and reduced metastasis in the murine xenograft model by sequestering miR-96-5p and upregulating RASSF8. Correlation analyses in patient-derived NSCLC tumor specimens supported the involvement of the circPTPRA/miR-96-5p/RASSF8/E-cadherin axis dysregulation in NSCLC tumor progression. INTERPRETATION: circPTPRA suppresses EMT and metastasis of NSCLC cell lines by sponging miR-96-5p, which upregulates the downstream tumor suppressor RASSF8. The circPTPRA/miR-96-5p/RASSF8/E-cadherin axis can be leveraged as a potential treatment avenue in NSCLC. FUND: The Key research and development projects of Anhui Province (201904a0720079), the Natural Science Foundation of Anhui Province (1908085MH240), the Graduate Innovation Program of Bengbu Medical College (Byycx1843), the National Natural Science Foundation of Tibet (XZ2017ZR-ZY033) and the Science and Technology Project of Shannan (SNKJYFJF2017-3) and Academic Subsidy Project for Top Talents in Universities of Anhui in 2019 (gxbjZD16).


Subject(s)
Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Non-Small-Cell Lung/pathology , Epithelial-Mesenchymal Transition/genetics , Lung Neoplasms/genetics , Lung Neoplasms/pathology , MicroRNAs/genetics , RNA, Circular/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Animals , Cadherins/genetics , Cadherins/metabolism , Carcinoma, Non-Small-Cell Lung/mortality , Carcinoma, Non-Small-Cell Lung/therapy , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic , Humans , In Situ Hybridization, Fluorescence , Lung Neoplasms/mortality , Lung Neoplasms/therapy , Mice , Neoplasm Metastasis , Neoplasm Staging , Phenotype , RNA Interference
12.
Nat Commun ; 10(1): 2193, 2019 05 16.
Article in English | MEDLINE | ID: mdl-31097705

ABSTRACT

Filamentous actin (F-actin) networks facilitate key processes like cell shape control, division, polarization and motility. The dynamic coordination of F-actin networks and its impact on cellular activities are poorly understood. We report an antagonistic relationship between endosomal F-actin assembly and cortical actin bundle integrity during Drosophila airway maturation. Double mutants lacking receptor tyrosine phosphatases (PTP) Ptp10D and Ptp4E, clear luminal proteins and disassemble apical actin bundles prematurely. These defects are counterbalanced by reduction of endosomal trafficking and by mutations affecting the tyrosine kinase Btk29A, and the actin nucleation factor WASH. Btk29A forms protein complexes with Ptp10D and WASH, and Btk29A phosphorylates WASH. This phosphorylation activates endosomal WASH function in flies and mice. In contrast, a phospho-mimetic WASH variant induces endosomal actin accumulation, premature luminal endocytosis and cortical F-actin disassembly. We conclude that PTPs and Btk29A regulate WASH activity to balance the endosomal and cortical F-actin networks during epithelial tube maturation.


Subject(s)
Drosophila Proteins/metabolism , Endosomes/metabolism , Morphogenesis/physiology , Protein-Tyrosine Kinases/metabolism , Vesicular Transport Proteins/metabolism , Actins/metabolism , Animals , Animals, Genetically Modified , Cell Line , Drosophila Proteins/genetics , Drosophila melanogaster , Embryo, Nonmammalian/diagnostic imaging , Epithelium/diagnostic imaging , Epithelium/growth & development , Fibroblasts , Intravital Microscopy , Mice , Microfilament Proteins/genetics , Microfilament Proteins/metabolism , Microscopy, Confocal , Phosphorylation/physiology , Protein Tyrosine Phosphatases/genetics , Protein Tyrosine Phosphatases/metabolism , Protein-Tyrosine Kinases/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Respiratory System/diagnostic imaging , Respiratory System/growth & development , Vesicular Transport Proteins/genetics
13.
J Cell Sci ; 132(7)2019 04 03.
Article in English | MEDLINE | ID: mdl-30837287

ABSTRACT

Many neurons influence their targets through co-release of neuropeptides and small-molecule transmitters. Neuropeptides are packaged into dense-core vesicles (DCVs) in the soma and then transported to synapses, while small-molecule transmitters such as monoamines are packaged by vesicular transporters that function at synapses. These separate packaging mechanisms point to activity, by inducing co-release as the sole scaler of co-transmission. Based on screening in Drosophila for increased presynaptic neuropeptides, the receptor protein tyrosine phosphatase (Rptp) Ptp4E was found to post-transcriptionally regulate neuropeptide content in single DCVs at octopamine synapses. This occurs without changing neuropeptide release efficiency, transport and DCV size measured by both stimulated emission depletion super-resolution and transmission electron microscopy. Ptp4E also controls the presynaptic abundance and activity of the vesicular monoamine transporter (VMAT), which packages monoamine transmitters for synaptic release. Thus, rather than rely on altering electrical activity, the Rptp regulates packaging underlying monoamine-neuropeptide co-transmission by controlling vesicular membrane transporter and luminal neuropeptide content.This article has an associated First Person interview with the first author of the paper.


Subject(s)
Drosophila Proteins/genetics , Drosophila/genetics , Neuropeptides/physiology , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Transport Vesicles/physiology , Animals , Axons/physiology , Drosophila Proteins/physiology , Female , Gene Expression Regulation, Developmental , Male , Neurons/physiology , Receptor-Like Protein Tyrosine Phosphatases, Class 4/physiology , Secretory Vesicles/physiology , Synapses/physiology , Synaptic Vesicles/physiology
14.
FASEB J ; 33(4): 5101-5111, 2019 04.
Article in English | MEDLINE | ID: mdl-30615487

ABSTRACT

Understanding how body weight is regulated at the molecular level is essential for treating obesity. We show that female mice genetically lacking protein tyrosine phosphatase (PTP) receptor type α (PTPRA) exhibit reduced weight and adiposity and increased energy expenditure, and are more resistant to diet-induced obesity than matched wild-type control mice. These mice also exhibit reduced levels of circulating leptin and are leptin hypersensitive, suggesting that PTPRA inhibits leptin signaling in the hypothalamus. Male and female PTPRA-deficient mice fed a high-fat diet were leaner and displayed increased metabolic rates and lower circulating leptin levels, indicating that the effects of loss of PTPRA persist in the obese state. Molecularly, PTPRA down-regulates leptin receptor signaling by dephosphorylating the receptor-associated kinase JAK2, with which the phosphatase associates constitutively. In contrast to the closely related tyrosine phosphatase ε, leptin induces only weak phosphorylation of PTPRA at its C-terminal regulatory site Y789, and this does not affect the activity of PTPRA toward JAK2. PTPRA is therefore an inhibitor of hypothalamic leptin signaling in vivo and may prevent premature activation of leptin signaling, as well as return signaling to baseline after exposure to leptin.-Cohen-Sharir, Y., Kuperman, Y., Apelblat, D., den Hertog, J., Spiegel, I., Knobler, H., Elson, A. Protein tyrosine phosphatase alpha inhibits hypothalamic leptin receptor signaling and regulates body weight in vivo.


Subject(s)
Hypothalamus/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Receptors, Leptin/metabolism , Adiposity/physiology , Animals , Body Weight/physiology , Female , Janus Kinase 2/metabolism , Leptin/metabolism , Male , Mice, Knockout , Obesity/metabolism , Phosphorylation/physiology , Physical Conditioning, Animal/physiology , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Signal Transduction/physiology
15.
Schizophr Res ; 206: 75-81, 2019 04.
Article in English | MEDLINE | ID: mdl-30594456

ABSTRACT

The contribution of both common and rare risk variants to the genetic architecture of schizophrenia (SZ) has been documented in genome-wide association studies, whole exome and whole genome sequencing approaches. As SZ is highly heritable and segregates in families, highly penetrant rare variants are more likely to be identified through analyses of multiply affected families. Further, much of the gene mapping studies in SZ have utilized individuals of Caucasian ancestry. Analysis of other ethnic groups may be informative. In this study, we aimed at identification of rare, penetrant risk variants utilizing whole exome sequencing (WES) in a three-generation Indian family with multiple members affected. Filtered data from WES, combined with in silico analyses revealed a novel heterozygous missense variant (NM_080841:c.1730C>G:p.T577R; exon18) in Protein tyrosine phosphatase, receptor type A (PTPRA 20p13). The variant was located in an evolutionarily conserved position and predicted to be damaging. Screening for variants in this gene in the WES data of an independent SZ cohort (n = 350) of matched ethnicity, identified five additional rare missense variants with MAF < 0.003, which were also predicted to be damaging. In conclusion, the rare missense variants in PTPRA identified in this study could confer risk for SZ. This has also derived support from concordant data from prior linkage and association, as well as animal studies which indicated a role for PTPRA in glutamate function.


Subject(s)
Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Schizophrenia/genetics , Cohort Studies , Computer Simulation , Family , Female , Genetic Predisposition to Disease , Humans , India , Male , Mutation, Missense , Pedigree , Polymorphism, Single Nucleotide , Exome Sequencing
16.
Acta Crystallogr D Struct Biol ; 74(Pt 10): 1015-1026, 2018 Oct 01.
Article in English | MEDLINE | ID: mdl-30289412

ABSTRACT

Here, new crystal structures are presented of the isolated membrane-proximal D1 and distal D2 domains of protein tyrosine phosphatase epsilon (PTPℇ), a protein tyrosine phosphatase that has been shown to play a positive role in the survival of human breast cancer cells. A triple mutant of the PTPℇ D2 domain (A455N/V457Y/E597D) was also constructed to reconstitute the residues of the PTPℇ D1 catalytic domain that are important for phosphatase activity, resulting in only a slight increase in the phosphatase activity compared with the native D2 protein. The structures reported here are of sufficient resolution for structure-based drug design, and a microarray-based assay for high-throughput screening to identify small-molecule inhibitors of the PTPℇ D1 domain is also described.


Subject(s)
Drug Design , Protein Array Analysis/methods , Protein Domains/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/chemistry , Crystallography, X-Ray/methods , Humans , Protein Structure, Tertiary , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Small Molecule Libraries
17.
J Cell Sci ; 131(15)2018 08 06.
Article in English | MEDLINE | ID: mdl-29991512

ABSTRACT

Extrinsic signals that regulate oligodendrocyte maturation and subsequent myelination are essential for central nervous system development and regeneration. Deficiency in the extracellular factor laminin-2 (Lm2, comprising the α2ß1γ1 chains), as occurs in congenital muscular dystrophy, can lead to impaired oligodendroglial development and aberrant myelination, but many aspects of Lm2-regulated oligodendroglial signaling and differentiation remain undefined. We show that receptor-like protein tyrosine phosphatase α (PTPα, also known as PTPRA) is essential for myelin basic protein expression and cell spreading during Lm2-induced oligodendrocyte differentiation. PTPα complexes with the Lm2 receptors α6ß1 integrin and dystroglycan to transduce Fyn activation upon Lm2 engagement. In this way, PTPα mediates a subset of Lm2-induced signals required for differentiation, includeing mTOR-dependent Akt activation but not Erk1/2 activation. We identify N-myc downstream regulated gene-1 (NDRG1) as a PTPα-regulated molecule during oligodendrocyte differentiation, and distinguish Lm2 receptor-specific modes of Fyn-Akt-dependent and -independent NDRG1 phosphorylation. Altogether, this reveals an Lm2-regulated PTPα-Fyn-Akt signaling axis that is critical for key aspects of the gene expression and morphological changes that mark oligodendrocyte maturation.


Subject(s)
Laminin/metabolism , Oligodendroglia/cytology , Oligodendroglia/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Proto-Oncogene Proteins c-fyn/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Animals , Cell Differentiation/genetics , Cell Differentiation/physiology , Cells, Cultured , Female , Immunoblotting , Immunohistochemistry , Immunoprecipitation , Male , Mice , Mice, Inbred C57BL , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-fyn/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Signal Transduction/genetics , Signal Transduction/physiology
18.
J Mol Neurosci ; 62(3-4): 329-343, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28647856

ABSTRACT

CNS myelination defects occur in mice deficient in receptor-like protein tyrosine phosphatase alpha (PTPα). Here, we investigated the role of PTPα in oligodendrocyte differentiation and myelination using cells and tissues from wild-type (WT) and PTPα knockout (KO) mice. PTPα promoted the timely differentiation of neural stem cell-derived oligodendrocyte progenitor cells (OPCs). Compared to WT OPCs, KO OPC cultures had more NG2+ progenitors, fewer myelin basic protein (MBP)+ oligodendrocytes, and reduced morphological complexity. In longer co-cultures with WT neurons, more KO than WT OPCs remained NG2+ and while equivalent MBP+ populations of WT and KO cells formed, the reduced area occupied by the MBP+ KO cells suggested that their morphological maturation was impeded. These defects were associated with reduced myelin formation in KO OPC/WT neuron co-cultures. Myelin formation was also impaired when WT OPCs were co-cultured with KO neurons, revealing a novel role for neuronal PTPα in myelination. Canonical Wnt/ß-catenin signaling is an important regulator of OPC differentiation and myelination. Wnt signaling activity was not dysregulated in OPCs lacking PTPα, but suppression of Wnt signaling by the small molecule XAV939 remediated defects in KO oligodendrocyte differentiation and enhanced myelin formation by KO oligodendrocytes. However, the myelin segments that formed were significantly shorter than those produced by WT oligodendrocytes, raising the possibility of a role for glial PTPα in myelin extension distinct from its pro-differentiating actions. Altogether, this study reveals PTPα as a molecular coordinator of oligodendroglial and neuronal signals that controls multiple aspects of oligodendrocyte development and myelination.


Subject(s)
Myelin Sheath/metabolism , Neurogenesis , Neurons/metabolism , Oligodendroglia/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/metabolism , Animals , Antigens/metabolism , Cells, Cultured , Mice , Mice, Inbred C57BL , Myelin Basic Protein/metabolism , Neurons/cytology , Oligodendroglia/cytology , Proteoglycans/metabolism , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Wnt Signaling Pathway
19.
Int J Oncol ; 51(2): 489-497, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28656243

ABSTRACT

PTPRA is reported to be involved in cancer development and progression through activating the Src family kinase (SFK) signaling pathways, however, the roles of PTPRA in the squamous cell lung cancer (SCC) development are unclear. The purpose of this study was to clarify the clinical relevance and biological roles of PTPRA in SCC. We found that PTPRA was upregulated in squamous cell lung cancer compared to matched normal tissues at the mRNA (N=20, P=0.004) and protein expression levels (N=75, P<0.001). Notably, high mRNA level of PTPRA was significantly correlated with poorer prognosis in 675 SCC patients from the Kaplan-Meier plotter database. With 75 cases, we found that PTPRA protein expression was significantly correlated with tumor size (P=0.002), lymph node metastasis (P=0.008), depth of tumor invasion (P<0.001) and clinical stage (P<0.001). The Kaplan-Meier plot suggested that high expression of PTPRA had poorer overall survival in SCC patients (P=0.009). Multivariate Cox regression analysis suggested that PTPRA expression was an independent prognostic factor in SCC patients. In the cellular models, PTPRA promotes SCC cell proliferation through modulating Src activation as well as cell cycle progression. In conclusion, higher PTPRA level was associated with worse prognosis of SCC patients and PTPRA could promote the cell cycle progression through stimulating the c-Src signaling pathways.


Subject(s)
Lung Neoplasms/genetics , Neoplasms, Squamous Cell/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , src-Family Kinases/genetics , Aged , CSK Tyrosine-Protein Kinase , Cell Line, Tumor , Disease-Free Survival , Female , Gene Expression Regulation, Neoplastic/genetics , Humans , Kaplan-Meier Estimate , Lung Neoplasms/epidemiology , Lung Neoplasms/pathology , Lymphatic Metastasis/genetics , Lymphatic Metastasis/pathology , Male , Middle Aged , Neoplasms, Squamous Cell/epidemiology , Neoplasms, Squamous Cell/pathology , Prognosis , RNA, Messenger/genetics , Signal Transduction
20.
PLoS One ; 12(3): e0172887, 2017.
Article in English | MEDLINE | ID: mdl-28257417

ABSTRACT

Subtype R3 phosphotyrosine phosphatase receptors (R3 RPTPs) are single-spanning membrane proteins characterized by a unique modular composition of extracellular fibronectin repeats and a single cytoplasmatic protein tyrosine phosphatase (PTP) domain. Vertebrate R3 RPTPs consist of five members: PTPRB, PTPRJ, PTPRH and PTPRO, which dephosphorylate tyrosine residues, and PTPRQ, which dephosphorylates phophoinositides. R3 RPTPs are considered novel therapeutic targets in several pathologies such as ear diseases, nephrotic syndromes and cancer. R3 RPTP vertebrate receptors, as well as their known invertebrate counterparts from animal models: PTP52F, PTP10D and PTP4e from the fruitfly Drosophila melanogaster and F44G4.8/DEP-1 from the nematode Caenorhabditis elegans, participate in the regulation of cellular activities including cell growth and differentiation. Despite sharing structural and functional properties, the evolutionary relationships between vertebrate and invertebrate R3 RPTPs are not fully understood. Here we gathered R3 RPTPs from organisms covering a broad evolutionary distance, annotated their structure and analyzed their phylogenetic relationships. We show that R3 RPTPs (i) have probably originated in the common ancestor of animals (metazoans), (ii) are variants of a single ancestral gene in protostomes (arthropods, annelids and nematodes); (iii) a likely duplication of this ancestral gene in invertebrate deuterostomes (echinodermes, hemichordates and tunicates) generated the precursors of PTPRQ and PTPRB genes, and (iv) R3 RPTP groups are monophyletic in vertebrates and have specific conserved structural characteristics. These findings could have implications for the interpretation of past studies and provide a framework for future studies and functional analysis of this important family of proteins.


Subject(s)
Evolution, Molecular , Phylogeny , Receptor-Like Protein Tyrosine Phosphatases, Class 3/genetics , Animals , Caenorhabditis elegans/genetics , Cell Differentiation/genetics , Conserved Sequence/genetics , Drosophila Proteins/genetics , Drosophila melanogaster/genetics , Humans , Protein Tyrosine Phosphatases/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 4/genetics , Signal Transduction/genetics
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