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1.
Am J Physiol Cell Physiol ; 326(6): C1605-C1610, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38646783

RESUMO

G protein-coupled receptors (GPCRs) are ubiquitously expressed cell surface receptors that mediate numerous physiological responses and are highly druggable. Upon activation, GPCRs rapidly couple to heterotrimeric G proteins and are then phosphorylated and internalized from the cell surface. Recent studies indicate that GPCRs not only localize at the plasma membrane but also exist in intracellular compartments where they are competent to signal. Intracellular signaling by GPCRs is best described to occur at endosomes. Several studies have elegantly documented endosomal GPCR-G protein and GPCR-ß-arrestin signaling. Besides phosphorylation, GPCRs are also posttranslationally modified with ubiquitin. GPCR ubiquitination has been studied mainly in the context of receptor endosomal-lysosomal trafficking. However, new studies indicate that ubiquitination of endogenous GPCRs expressed in endothelial cells initiates the assembly of an intracellular p38 mitogen-activated kinase signaling complex that promotes inflammatory responses from endosomes. In this mini-review, we discuss emerging discoveries that provide critical insights into the function of ubiquitination in regulating GPCR inflammatory signaling at endosomes.


Assuntos
Endossomos , Inflamação , Receptores Acoplados a Proteínas G , Transdução de Sinais , Ubiquitina , Ubiquitinação , Endossomos/metabolismo , Humanos , Receptores Acoplados a Proteínas G/metabolismo , Animais , Inflamação/metabolismo , Inflamação/patologia , Ubiquitina/metabolismo , Fosforilação
3.
Mol Cell ; 83(21): 3766-3772, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37922871

RESUMO

Building a diverse laboratory that is equitable is critical for the retention of talent and the growth of trainees professionally and personally. Here, we outline several strategies including enhancing understanding of cultural competency and humility, establishing laboratory values, and developing equitable laboratory structures to create an inclusive laboratory environment to enable trainees to achieve their highest success.


Assuntos
Diversidade, Equidade, Inclusão , Laboratórios
4.
Cell ; 186(23): 4985-4991, 2023 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-37949054

RESUMO

Mexican, Puerto Rican, and Central American Ancestry (MPRCA) individuals represent 82% of US Latinos. An intergenerational group of MPRCA women and allies met to discuss persistent underrepresentation of MPRCA women in STEM, identifying multi-level challenges and solutions. Implementation of these solutions is important and will benefit MPRCA women and the entire academic community.


Assuntos
Hispânico ou Latino , Ciência , Feminino , Humanos , Estados Unidos , Ciência/educação
5.
J Biol Chem ; 299(12): 105370, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37865315

RESUMO

G protein-coupled receptors (GPCRs) are highly druggable and implicated in numerous diseases, including vascular inflammation. GPCR signals are transduced from the plasma membrane as well as from endosomes and controlled by posttranslational modifications. The thrombin-activated GPCR protease-activated receptor-1 is modified by ubiquitin. Ubiquitination of protease-activated receptor-1 drives recruitment of transforming growth factor-ß-activated kinase-1-binding protein 2 (TAB2) and coassociation of TAB1 on endosomes, which triggers p38 mitogen-activated protein kinase-dependent inflammatory responses in endothelial cells. Other endothelial GPCRs also induce p38 activation via a noncanonical TAB1-TAB2-dependent pathway. However, the regulatory processes that control GPCR ubiquitin-driven p38 inflammatory signaling remains poorly understood. We discovered mechanisms that turn on GPCR ubiquitin-dependent p38 signaling, however, the mechanisms that turn off the pathway are not known. We hypothesize that deubiquitination is an important step in regulating ubiquitin-driven p38 signaling. To identify specific deubiquitinating enzymes (DUBs) that control GPCR-p38 mitogen-activated protein kinase signaling, we conducted a siRNA library screen targeting 96 DUBs in endothelial cells and HeLa cells. We identified nine DUBs and validated the function two DUBs including cylindromatosis and ubiquitin-specific protease-34 that specifically regulate thrombin-induced p38 phosphorylation. Depletion of cylindromatosis expression by siRNA enhanced thrombin-stimulated p38 signaling, endothelial barrier permeability, and increased interleukin-6 cytokine expression. Conversely, siRNA knockdown of ubiquitin-specific protease-34 expression decreased thrombin-promoted interleukin-6 expression and had no effect on thrombin-induced endothelial barrier permeability. These studies suggest that specific DUBs distinctly regulate GPCR-induced p38-mediated inflammatory responses.


Assuntos
Enzima Desubiquitinante CYLD , Enzimas Desubiquitinantes , Células Endoteliais , Trombina , Humanos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Enzima Desubiquitinante CYLD/metabolismo , Enzimas Desubiquitinantes/metabolismo , Células Endoteliais/metabolismo , Células HeLa , Interleucina-6/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Receptor PAR-1/metabolismo , RNA Interferente Pequeno/metabolismo , Trombina/farmacologia , Trombina/metabolismo , Ubiquitina/metabolismo , Proteases Específicas de Ubiquitina/metabolismo , Linhagem Celular , Regulação Enzimológica da Expressão Gênica , Fosforilação/genética
6.
Front Mol Biosci ; 10: 1211597, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37692066

RESUMO

Introduction: Dysfunction of the endothelium impairs its' protective role and promotes inflammation and progression of vascular diseases. Activated Protein C (APC) elicits endothelial cytoprotective responses including barrier stabilization, anti-inflammatory and anti-apoptotic responses through the activation of the G protein-coupled receptor (GPCR) protease-activated receptor-1 (PAR1) and is a promising therapeutic. Despite recent advancements in developing new Activated protein C variants with clinical potential, the mechanism by which APC/PAR1 promotes different cytoprotective responses remains unclear and is important to understand to advance Activated protein C and new targets as future therapeutics. Here we examined the mechanisms by which APC/PAR1 attenuates cytokine-induced pro-inflammatory vascular cell adhesion molecule (VCAM-1) expression, a key mediator of endothelial inflammatory responses. Methods: Quantitative multiplexed mass spectrometry analysis of Activated protein C treated endothelial cells, endothelial cell transcriptomics database (EndoDB) online repository queries, biochemical measurements of protein expression, quantitative real-time polymerase chain reaction (RT-qPCR) measurement of mRNA transcript abundance, pharmacological inhibitors and siRNA transfections of human cultured endothelial cells. Results: Here we report that Activated Protein C modulates phosphorylation of tumor necrosis factor (TNF)-α signaling pathway components and attenuates of TNF-α induced VCAM-1 expression independent of mRNA stability. Unexpectedly, we found a critical role for the G protein-coupled receptor co-receptor sphingosine-1 phosphate receptor-1 (S1PR1) and the G protein receptor kinase-2 (GRK2) in mediating APC/PAR1 anti-inflammatory responses in endothelial cells. Discussion: This study provides new knowledge of the mechanisms by which different APC/PAR1 cytoprotective responses are mediated through discrete ß-arrestin-2-driven signaling pathways modulated by specific G protein-coupled receptor co-receptors and GRKs.

7.
Mol Biol Cell ; 34(9): ar93, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37223976

RESUMO

The α-arrestin ARRDC3 is a recently discovered tumor suppressor in invasive breast cancer that functions as a multifaceted adaptor protein to control protein trafficking and cellular signaling. However, the molecular mechanisms that control ARRDC3 function are unknown. Other arrestins are known to be regulated by posttranslational modifications, suggesting that ARRDC3 may be subject to similar regulatory mechanisms. Here we report that ubiquitination is a key regulator of ARRDC3 function and is mediated primarily by two proline-rich PPXY motifs in the ARRDC3 C-tail domain. Ubiquitination and the PPXY motifs are essential for ARRDC3 function in regulating GPCR trafficking and signaling. Additionally, ubiquitination and the PPXY motifs mediate ARRDC3 protein degradation, dictate ARRDC3 subcellular localization, and are required for interaction with the NEDD4-family E3 ubiquitin ligase WWP2. These studies demonstrate a role for ubiquitination in regulating ARRDC3 function and reveal a mechanism by which ARRDC3 divergent functions are controlled.


Assuntos
Arrestina , Arrestinas , Arrestina/metabolismo , Ubiquitinação , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Arrestinas/metabolismo , Transdução de Sinais , Ubiquitina-Proteína Ligases/metabolismo
8.
J Neurosci ; 43(21): 3970-3984, 2023 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-37019623

RESUMO

Endolysosomal defects in neurons are central to the pathogenesis of prion and other neurodegenerative disorders. In prion disease, prion oligomers traffic through the multivesicular body (MVB) and are routed for degradation in lysosomes or for release in exosomes, yet how prions impact proteostatic pathways is unclear. We found that prion-affected human and mouse brain showed a marked reduction in Hrs and STAM1 (ESCRT-0), which route ubiquitinated membrane proteins from early endosomes into MVBs. To determine how the reduction in ESCRT-0 impacts prion conversion and cellular toxicity in vivo, we prion-challenged conditional knockout mice (male and female) having Hrs deleted from neurons, astrocytes, or microglia. The neuronal, but not astrocytic or microglial, Hrs-depleted mice showed a shortened survival and an acceleration in synaptic derangements, including an accumulation of ubiquitinated proteins, deregulation of phosphorylated AMPA and metabotropic glutamate receptors, and profoundly altered synaptic structure, all of which occurred later in the prion-infected control mice. Finally, we found that neuronal Hrs (nHrs) depletion increased surface levels of the cellular prion protein, PrPC, which may contribute to the rapidly advancing disease through neurotoxic signaling. Taken together, the reduced Hrs in the prion-affected brain hampers ubiquitinated protein clearance at the synapse, exacerbates postsynaptic glutamate receptor deregulation, and accelerates neurodegeneration.SIGNIFICANCE STATEMENT Prion diseases are rapidly progressive neurodegenerative disorders characterized by prion aggregate spread through the central nervous system. Early disease features include ubiquitinated protein accumulation and synapse loss. Here, we investigate how prion aggregates alter ubiquitinated protein clearance pathways (ESCRT) in mouse and human prion-infected brain, discovering a marked reduction in Hrs. Using a prion-infection mouse model with neuronal Hrs (nHrs) depleted, we show that low neuronal Hrs is detrimental and markedly shortens survival time while accelerating synaptic derangements, including ubiquitinated protein accumulation, indicating that Hrs loss exacerbates prion disease progression. Additionally, Hrs depletion increases the surface distribution of prion protein (PrPC), linked to aggregate-induced neurotoxic signaling, suggesting that Hrs loss in prion disease accelerates disease through enhancing PrPC-mediated neurotoxic signaling.


Assuntos
Doenças Neurodegenerativas , Doenças Priônicas , Príons , Masculino , Feminino , Camundongos , Humanos , Animais , Príons/metabolismo , Proteínas Priônicas/metabolismo , Receptores de AMPA/metabolismo , Neurônios/metabolismo , Doenças Priônicas/metabolismo , Doenças Priônicas/patologia , Doenças Neurodegenerativas/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo
9.
Trends Biochem Sci ; 47(9): 725-727, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35606213

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic has created unprecedented obstacles for new investigators to traverse. The pandemic's impact exacerbates inequities for groups historically excluded from science. We provide recommendations to support junior faculty, including women and faculty from groups historically excluded from science, in establishing laboratories during the pandemic and foreseeable future.


Assuntos
COVID-19 , Pandemias , Feminino , Humanos , Laboratórios
10.
J Clin Transl Sci ; 6(1): e18, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35291213

RESUMO

Introduction: Mentorship is critical for faculty success, satisfaction, and engagement. However, many faculty, particularly underrepresented racial/ethnic (UR) faculty, lack access to high-quality mentoring. In an effort to improve mentoring for all faculty, we developed and implemented a formally structured faculty mentor training program (FMTP) across UC San Diego Health Sciences, which included institutional support, mentorship training, and department/division mentorship programs. Methods: FMTP impact was evaluated using three primary outcome variables: mentoring quality, mentoring behaviors, and institutional climate. Participants' self-assessed mentoring competencies were measured using validated instruments. Results: A total of 391 (23%) of Health Sciences faculty participated in FMTP. Participation rate was higher for women than men (30% versus 17%) and highest for UR faculty (39%). FMTP was implemented in 16 of 19 departments. Self-reported mentoring improved for FMTP participants with mentoring quality (p = 0.009) and meeting mentees' expectations (p = 0.01) continuing to improve for up to 2 years after training. However, participants were unsure if they were meeting UR mentees' expectations. FMTP participants were significantly more satisfied with mentoring quality (p < 0.001) compared to non-participants, with the greatest increase in satisfaction reported by UR faculty (38-61%). UR faculty reported improved overall morale (51-61%) and a perception that the environment was supportive for UR faculty (48-70%). Conclusion: The implementation of a system-wide formal structured FMTP was associated with improved faculty satisfaction, quality of mentoring, and institutional climate, especially for UR faculty.

11.
J Biol Chem ; 298(4): 101801, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35257745

RESUMO

Endothelial dysfunction is a hallmark of inflammation and is mediated by inflammatory factors that signal through G protein-coupled receptors including protease-activated receptor-1 (PAR1). PAR1, a receptor for thrombin, signals via the small GTPase RhoA and myosin light chain intermediates to facilitate endothelial barrier permeability. PAR1 also induces endothelial barrier disruption through a p38 mitogen-activated protein kinase-dependent pathway, which does not integrate into the RhoA/MLC pathway; however, the PAR1-p38 signaling pathways that promote endothelial dysfunction remain poorly defined. To identify effectors of this pathway, we performed a global phosphoproteome analysis of thrombin signaling regulated by p38 in human cultured endothelial cells using multiplexed quantitative mass spectrometry. We identified 5491 unique phosphopeptides and 2317 phosphoproteins, four distinct dynamic phosphoproteome profiles of thrombin-p38 signaling, and an enrichment of biological functions associated with endothelial dysfunction, including modulators of endothelial barrier disruption and a subset of kinases predicted to regulate p38-dependent thrombin signaling. Using available antibodies to detect identified phosphosites of key p38-regulated proteins, we discovered that inhibition of p38 activity and siRNA-targeted depletion of the p38α isoform increased basal phosphorylation of extracellular signal-regulated protein kinase 1/2, resulting in amplified thrombin-stimulated extracellular signal-regulated protein kinase 1/2 phosphorylation that was dependent on PAR1. We also discovered a role for p38 in the phosphorylation of α-catenin, a component of adherens junctions, suggesting that this phosphorylation may function as an important regulatory process. Taken together, these studies define a rich array of thrombin- and p38-regulated candidate proteins that may serve important roles in endothelial dysfunction.


Assuntos
Células Endoteliais , Trombina , Proteínas Quinases p38 Ativadas por Mitógeno , Células Cultivadas , Células Endoteliais/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases , Fosforilação , Proteômica , Receptor PAR-1/metabolismo , Trombina/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
12.
Mol Biol Cell ; 33(3): vo1, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35179995

RESUMO

Despite substantial investment and effort by federal agencies and institutions to improve the diversity of the professoriate, progress is excruciatingly slow. One program that aims to enhance faculty diversity is the Institutional Research and Academic Career Development Award (IRACDA) funded by the National Institutes of Health/National Institute of General Medical Sciences. IRACDA supports the training of a diverse cohort of postdoctoral scholars who will seek academic research and teaching careers. The San Diego IRACDA program has trained 109 postdoctoral scholars since its inception in 2003; 59% are women and 63% are underrepresented (UR) Black/African-American, Latinx/Mexican-American, and Indigenous scientists. Sixty-four percent obtained tenure-track faculty positions, including a substantial 32% at research-intensive institutions. However, the COVID-19 pandemic crisis threatens to upend IRACDA efforts to improve faculty diversity, and academia is at risk of losing a generation of diverse, talented scholars. Here, a group of San Diego IRACDA postdoctoral scholars reflects on these issues and discusses recommendations to enhance the retention of UR scientists to avoid a "lost generation" of promising UR faculty scholars.


Assuntos
COVID-19 , Diversidade Cultural , Educação de Pós-Graduação , Docentes de Medicina/estatística & dados numéricos , Bolsas de Estudo/estatística & dados numéricos , Pandemias , SARS-CoV-2 , Universidades/estatística & dados numéricos , California , Educação de Pós-Graduação/economia , Etnicidade/estatística & dados numéricos , Docentes de Medicina/economia , Feminino , Humanos , Masculino , Grupos Minoritários/estatística & dados numéricos , National Institute of General Medical Sciences (U.S.) , National Institutes of Health (U.S.) , Pesquisadores/economia , Pesquisadores/educação , Pesquisadores/estatística & dados numéricos , Salários e Benefícios/estatística & dados numéricos , Estados Unidos , Universidades/economia , Mulheres/educação
13.
Antioxid Redox Signal ; 36(13-15): 1066-1079, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34465145

RESUMO

Significance: Adaptor proteins control the spatiotemporal dynamics of cellular signaling. Dysregulation of adaptor protein function can cause aberrant cell signaling and promote cancer. The arrestin family of adaptor proteins are known to regulate signaling by the superfamily of G protein-coupled receptors (GPCRs). The GPCRs are highly druggable and implicated in cancer progression. However, the molecular mechanisms responsible for arrestin dysregulation and the impact on GPCR function in cancer have yet to be fully elucidated. Recent Advances: A new family of mammalian arrestins, termed the α-arrestins, was recently discovered. The α-arrestin, arrestin domain-containing protein 3 (ARRDC3), in particular, has been identified as a tumor suppressor and is reported to control cellular signaling of GPCRs in cancer. Critical Issues: Compared with the extensively studied mammalian ß-arrestins, there is limited information regarding the regulatory mechanisms that control α-arrestin activation and function. Here, we discuss the molecular mechanisms that regulate ARRDC3, which include post-translational modifications such as phosphorylation and ubiquitination. We also provide evidence that ARRDC3 can interact with a wide array of proteins that control diverse biological functions. Future Directions: ARRDC3 interacts with numerous proteins and is likely to display diverse functions in cancer, metabolic disease, and other syndromes. Thus, understanding the regulatory mechanisms of ARRDC3 activity in various cellular contexts is critically important. Recent studies suggest that α-arrestins may be regulated through post-translational modification, which is known to impact adaptor protein function. However, additional studies are needed to determine how these regulatory mechanisms affect ARRDC3 tumor suppressor function. Antioxid. Redox Signal. 36, 1066-1079.


Assuntos
Arrestina , Neoplasias , Proteínas Adaptadoras de Transdução de Sinal , Animais , Arrestina/metabolismo , Arrestinas/genética , Arrestinas/metabolismo , Mamíferos/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Ubiquitinação
14.
Proc Natl Acad Sci U S A ; 118(49)2021 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-34873055

RESUMO

Endothelial dysfunction is associated with vascular disease and results in disruption of endothelial barrier function and increased sensitivity to apoptosis. Currently, there are limited treatments for improving endothelial dysfunction. Activated protein C (aPC), a promising therapeutic, signals via protease-activated receptor-1 (PAR1) and mediates several cytoprotective responses, including endothelial barrier stabilization and anti-apoptotic responses. We showed that aPC-activated PAR1 signals preferentially via ß-arrestin-2 (ß-arr2) and dishevelled-2 (Dvl2) scaffolds rather than G proteins to promote Rac1 activation and barrier protection. However, the signaling pathways utilized by aPC/PAR1 to mediate anti-apoptotic activities are not known. aPC/PAR1 cytoprotective responses also require coreceptors; however, it is not clear how coreceptors impact different aPC/PAR1 signaling pathways to drive distinct cytoprotective responses. Here, we define a ß-arr2-mediated sphingosine kinase-1 (SphK1)-sphingosine-1-phosphate receptor-1 (S1PR1)-Akt signaling axis that confers aPC/PAR1-mediated protection against cell death. Using human cultured endothelial cells, we found that endogenous PAR1 and S1PR1 coexist in caveolin-1 (Cav1)-rich microdomains and that S1PR1 coassociation with Cav1 is increased by aPC activation of PAR1. Our study further shows that aPC stimulates ß-arr2-dependent SphK1 activation independent of Dvl2 and is required for transactivation of S1PR1-Akt signaling and protection against cell death. While aPC/PAR1-induced, extracellular signal-regulated kinase 1/2 (ERK1/2) activation is also dependent on ß-arr2, neither SphK1 nor S1PR1 are integrated into the ERK1/2 pathway. Finally, aPC activation of PAR1-ß-arr2-mediated protection against apoptosis is dependent on Cav1, the principal structural protein of endothelial caveolae. These studies reveal that different aPC/PAR1 cytoprotective responses are mediated by discrete, ß-arr2-driven signaling pathways in caveolae.


Assuntos
Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Proteína C/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor PAR-1/metabolismo , Receptores de Esfingosina-1-Fosfato/metabolismo , beta-Arrestina 2/metabolismo , Anilidas/farmacologia , Apoptose/fisiologia , Células Endoteliais/fisiologia , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Lactonas/farmacologia , Metanol/farmacologia , Organofosfonatos/farmacologia , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Inibidores da Agregação Plaquetária/farmacologia , Proteína C/genética , Proteínas Proto-Oncogênicas c-akt/genética , Piridinas/farmacologia , Pirrolidinas/farmacologia , Receptor PAR-1/genética , Receptores de Esfingosina-1-Fosfato/genética , Sulfonas/farmacologia , beta-Arrestina 2/genética
15.
Sci Signal ; 14(698): eabc1044, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34516752

RESUMO

Vascular inflammation causes endothelial barrier disruption and tissue edema. Several inflammatory mediators act through G protein­coupled receptors (GPCRs), including protease-activated receptor-1 (PAR1), to elicit inflammatory responses. The activation of PAR1 by its ligand thrombin stimulates proinflammatory, p38 mitogen-activated protein kinase (MAPK) signaling that promotes endothelial barrier disruption. Through mass spectrometry phosphoproteomics, we identified heat shock protein 27 (HSP27), which exists as a large oligomer that binds to actin, as a promising candidate for the p38-mediated regulation of barrier integrity. Depletion of HSP27 by siRNA enhanced endothelial cell barrier permeability and slowed recovery after thrombin stimulation. We further showed that two effector kinases of p38 MAPK, MAPKAPK2 (MK2) and MAPKAPK3 (MK3), differentially phosphorylated HSP27 at Ser15, Ser78, and Ser82. Whereas inhibition of thrombin-stimulated p38 activation blocked HSP27 phosphorylation at all three sites, inhibition of MK2 reduced the phosphorylation of only Ser15 and Ser78. Inhibition of both MK2 and MK3 was necessary to attenuate Ser82 phosphorylation. Thrombin-stimulated p38-MK2-MK3 signaling induced HSP27 oligomer disassembly. However, a phosphorylation-deficient mutant of HSP27 exhibited defective oligomer disassembly and altered the dynamics of barrier recovery after thrombin stimulation. Moreover, blocking HSP27 oligomer reassembly with the small-molecule inhibitor J2 enhanced endothelial barrier permeability in vitro and vascular leakage in vivo in response to PAR1 activation. These studies reveal the distinct regulation of HSP27 phosphorylation and function induced by the GPCR-stimulated p38-MK2-MK3 signaling axis that controls the dynamics of endothelial barrier recovery in vitro and vascular leakage in vivo.


Assuntos
Proteínas de Choque Térmico HSP27
16.
J Cell Sci ; 134(8)2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33722977

RESUMO

The α-arrestin domain containing protein 3 (ARRDC3) is a tumor suppressor in triple-negative breast carcinoma (TNBC), a highly metastatic subtype of breast cancer that lacks targeted therapies. Thus, understanding the mechanisms and targets of ARRDC3 in TNBC is important. ARRDC3 regulates trafficking of protease-activated receptor 1 (PAR1, also known as F2R), a G-protein-coupled receptor (GPCR) implicated in breast cancer metastasis. Loss of ARRDC3 causes overexpression of PAR1 and aberrant signaling. Moreover, dysregulation of GPCR-induced Hippo signaling is associated with breast cancer progression. However, the mechanisms responsible for Hippo dysregulation remain unknown. Here, we report that the Hippo pathway transcriptional co-activator TAZ (also known as WWTR1) is the major effector of GPCR signaling and is required for TNBC migration and invasion. Additionally, ARRDC3 suppresses PAR1-induced Hippo signaling via sequestration of TAZ, which occurs independently of ARRDC3-regulated PAR1 trafficking. The ARRDC3 C-terminal PPXY motifs and TAZ WW domain are crucial for this interaction and are required for suppression of TNBC migration and lung metastasis in vivo. These studies are the first to demonstrate a role for ARRDC3 in regulating GPCR-induced TAZ activity in TNBC and reveal multi-faceted tumor suppressor functions of ARRDC3. This article has an associated First Person interview with the first author of the paper.


Assuntos
Neoplasias da Mama , Arrestinas/metabolismo , Neoplasias da Mama/genética , Feminino , Humanos , Receptor PAR-1/genética , Receptor PAR-1/metabolismo , Transdução de Sinais , Fatores de Transcrição
17.
Curr Opin Endocr Metab Res ; 16: 37-42, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32838054

RESUMO

G-coupled protein receptors (GPCRs) comprise the largest class of druggable targets. Signaling by GPCRs is initiated from subcellular hot spots including the plasma membrane, signalosomes, and endosomes to contribute to vascular inflammation. GPCR-G protein signaling at the plasma membrane causes endothelial barrier disruption and also cross-talks with growth factor receptors to promote proinflammatory signaling. A second surge of GPCR signaling is initiated by cytoplasmic NFκB activation mediated by ß-arrestins and CARMA-BCL10-MALT1 signalosomes. Once internalized, ubiquitinated GPCRs initiate signaling from endosomes via assembly of the transforming growth factor-ß-activated kinase binding protein-1 (TAB1)-TAB2-p38 MAPK complex to promote vascular inflammation. Understanding the complexities of GPCR signaling is critical for development of new strategies to treat vascular inflammation such as that associated with COVID-19.

18.
Pharmacol Rev ; 73(1): 120-151, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33268549

RESUMO

G protein-coupled receptors (GPCRs) are a large family comprising >800 signaling receptors that regulate numerous cellular and physiologic responses. GPCRs have been implicated in numerous diseases and represent the largest class of drug targets. Although advances in GPCR structure and pharmacology have improved drug discovery, the regulation of GPCR function by diverse post-translational modifications (PTMs) has received minimal attention. Over 200 PTMs are known to exist in mammalian cells, yet only a few have been reported for GPCRs. Early studies revealed phosphorylation as a major regulator of GPCR signaling, whereas later reports implicated a function for ubiquitination, glycosylation, and palmitoylation in GPCR biology. Although our knowledge of GPCR phosphorylation is extensive, our knowledge of the modifying enzymes, regulation, and function of other GPCR PTMs is limited. In this review we provide a comprehensive overview of GPCR post-translational modifications with a greater focus on new discoveries. We discuss the subcellular location and regulatory mechanisms that control post-translational modifications of GPCRs. The functional implications of newly discovered GPCR PTMs on receptor folding, biosynthesis, endocytic trafficking, dimerization, compartmentalized signaling, and biased signaling are also provided. Methods to detect and study GPCR PTMs as well as PTM crosstalk are further highlighted. Finally, we conclude with a discussion of the implications of GPCR PTMs in human disease and their importance for drug discovery. SIGNIFICANCE STATEMENT: Post-translational modification of G protein-coupled receptors (GPCRs) controls all aspects of receptor function; however, the detection and study of diverse types of GPCR modifications are limited. A thorough understanding of the role and mechanisms by which diverse post-translational modifications regulate GPCR signaling and trafficking is essential for understanding dysregulated mechanisms in disease and for improving and refining drug development for GPCRs.


Assuntos
Processamento de Proteína Pós-Traducional , Receptores Acoplados a Proteínas G , Animais , Humanos , Fosforilação , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Ubiquitinação
19.
Nat Commun ; 11(1): 6088, 2020 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-33257668

RESUMO

The mechanistic target of rapamycin complex 1 (mTORC1) integrates growth, nutrient and energy status cues to control cell growth and metabolism. While mTORC1 activation at the lysosome is well characterized, it is not clear how this complex is regulated at other subcellular locations. Here, we combine location-selective kinase inhibition, live-cell imaging and biochemical assays to probe the regulation of growth factor-induced mTORC1 activity in the nucleus. Using a nuclear targeted Akt Substrate-based Tandem Occupancy Peptide Sponge (Akt-STOPS) that we developed for specific inhibition of Akt, a critical upstream kinase, we show that growth factor-stimulated nuclear mTORC1 activity requires nuclear Akt activity. Further mechanistic dissection suggests that nuclear Akt activity mediates growth factor-induced nuclear translocation of Raptor, a regulatory scaffolding component in mTORC1, and localization of Raptor to the nucleus results in nuclear mTORC1 activity in the absence of growth factor stimulation. Taken together, these results reveal a mode of regulation of mTORC1 that is distinct from its lysosomal activation, which controls mTORC1 activity in the nuclear compartment.


Assuntos
Núcleo Celular/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Camundongos , Células NIH 3T3 , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos
20.
Mol Biol Cell ; 31(25): 2752-2754, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33253072

RESUMO

The exclusion of Blacks/African-Americans, Latinx/Hispanics, and Indigenous people from science has resulted in their underrepresentation in the biomedical workforce, especially in academia. Faculty diversity at academic institutions is unacceptably low (<6%) and has remained unchanged in the past 20 years. Despite low representation, faculty of color are disproportionately tasked with service to enhance diversity and inclusion of the academy, often to the detriment of their research and academic success. This essay offers a perspective on the undue burden of service placed on underrepresented faculty to achieve institutional diversity and inclusion. I reflect on the challenges that faculty of color face trying to maintain a competitive research program while serving the needs of the academy, often in a capacity greater than that of their well-represented peers. I also discuss opportunities for faculty of color to leverage related diversity and inclusion work to boost their career progression and academic advancement.


Assuntos
Seleção de Pessoal/tendências , Universidades/ética , Universidades/tendências , Negro ou Afro-Americano , Pesquisa Biomédica , Diversidade Cultural , Docentes , Feminino , Hispânico ou Latino , Humanos , Masculino , Grupos Minoritários , Seleção de Pessoal/ética , Pesquisadores , Recursos Humanos
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