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1.
Heliyon ; 10(6): e27974, 2024 Mar 30.
Article En | MEDLINE | ID: mdl-38515669

Traditionally, public health surveillance relied on individual-level data but recently wastewater-based epidemiology (WBE) for the detection of infectious diseases including COVID-19 became a valuable tool in the public health arsenal. Here, we use WBE to follow the course of the COVID-19 pandemic in Rochester, Minnesota (population 121,395 at the 2020 census), from February 2021 to December 2022. We monitored the impact of SARS-CoV-2 infections on public health by comparing three sets of data: quantitative measurements of viral RNA in wastewater as an unbiased reporter of virus level in the community, positive results of viral RNA or antigen tests from nasal swabs reflecting community reporting, and hospitalization data. From February 2021 to August 2022 viral RNA levels in wastewater were closely correlated with the oscillating course of COVID-19 case and hospitalization numbers. However, from September 2022 cases remained low and hospitalization numbers dropped, whereas viral RNA levels in wastewater continued to oscillate. The low reported cases may reflect virulence reduction combined with abated inclination to report, and the divergence of virus levels in wastewater from reported cases may reflect COVID-19 shifting from pandemic to endemic. WBE, which also detects asymptomatic infections, can provide an early warning of impending cases, and offers crucial insights during pandemic waves and in the transition to the endemic phase.

2.
Physiol Biochem Zool ; 95(2): 122-129, 2022.
Article En | MEDLINE | ID: mdl-34986077

AbstractHibernation, a metabolic strategy, allows individuals to reduce energetic demands in times of energetic deficits. Hibernation is pervasive in nature, occurring in all major mammalian lineages and geographical regions; however, its expression is variable across species, populations, and individuals, suggesting that trade-offs are at play. Whereas hibernation reduces energy expenditure, energetically expensive arousals may impose physiological burdens. The torpor optimization hypothesis posits that hibernation should be expressed according to energy availability. The greater the energy surplus, the lower the hibernation output. The thrifty female hypothesis, a variation of the torpor optimization hypothesis, states that females should conserve more energy because of their more substantial reproductive costs. Contrarily, if hibernation's benefits offset its costs, hibernation may be maximized rather than optimized (e.g., hibernators with greater fat reserves could afford to hibernate longer). We assessed torpor expression in captive dwarf lemurs, primates that are obligate, seasonal, and tropical hibernators. Across 4.5 mo in winter, we subjected eight individuals at the Duke Lemur Center to conditions conducive to hibernation, recorded estimates of skin temperature hourly (a proxy for torpor), and determined body mass and tail fat reserves bimonthly. Across and between consecutive weigh-ins, heavier dwarf lemurs spent less time in torpor and lost more body mass. At equivalent body mass, females spent more time torpid and better conserved energy than did males. Although preliminary, our results support the torpor optimization and thrifty female hypotheses, suggesting that individuals optimize rather than maximize torpor according to body mass. These patterns are consistent with hibernation phenology in Madagascar, where dwarf lemurs hibernate longer in more seasonal habitats.


Cheirogaleidae , Hibernation , Torpor , Animals , Body Temperature , Energy Metabolism , Female , Male , Mammals , Seasons , Tail
3.
Arch Sex Behav ; 50(8): 3663-3673, 2021 11.
Article En | MEDLINE | ID: mdl-34327590

Men, relative to women, can benefit their total reproductive success by engaging in short-term pluralistic mating. Yet not all men enact such a mating strategy. It has previously been hypothesized that high mate value men should be most likely to adopt a short-term mating strategy, with this prediction being firmly grounded in some important mid-level evolutionary psychological theories. Yet evidence to support such a link has been mixed. This paper presents a comprehensive meta-analysis of 33 published and unpublished studies (N = 5928) in which we find that that self-reported mate value accounts for roughly 6% of variance in men's sociosexual orientation. The meta-analysis provides evidence that men's self-perceived mate value positively predicts their tendency to engage in short-term mating, but that the total effect size is small.


Men , Sexual Behavior , Female , Humans , Male , Reproduction , Sexual Partners
4.
Am J Med Genet A ; 185(9): 2653-2669, 2021 09.
Article En | MEDLINE | ID: mdl-33951288

Now in its 7th edition, Smith's Recognizable Patterns of Human Malformation was first published in 1970. This 1st edition comprised 135 "dysmorphic syndromes of multiple primary defects" and 12 "single syndromic malformations resulting in secondary defects." Of the former, other than a few chromosomal and environmental disorders, most were heritable conditions of then unknown etiology. In 2021, the majority of these conditions are now "solved," a notable exception is Hallermann-Streiff syndrome. The "solved" conditions were typically clinically delineated decades prior to understanding the underlying etiology, which rarely required recent technologies such as exome sequencing (ES) to elucidate. The 7th edition includes nearly 300 syndromes, sequences, and associations. An increasing number of conditions first appearing in the latest editions are sporadic, with many solved using either array CGH or ES. We have reviewed all syndromes that have appeared in "Smith's" with a focus on inheritance, heterogeneity, and year and method of etiologic discovery. Several themes emerge. Genetic heterogeneity and pleiotropy of genes are frequent. Several of the currently "unresolved" syndromes are clinically diverse such as Dubowitz syndrome. Multiple recurrent constellations of embryonic malformations, with VACTERL association as a paradigm, are increasingly likely to have a shared pathogenesis requiring further study.


Abnormalities, Multiple/pathology , Chromosomes, Human/genetics , Congenital Abnormalities/pathology , Gene-Environment Interaction , Genetic Predisposition to Disease , Abnormalities, Multiple/genetics , Abnormalities, Multiple/history , Congenital Abnormalities/genetics , History, 20th Century , History, 21st Century , Humans
5.
Nat Commun ; 12(1): 2558, 2021 05 07.
Article En | MEDLINE | ID: mdl-33963192

GEMIN5, an RNA-binding protein is essential for assembly of the survival motor neuron (SMN) protein complex and facilitates the formation of small nuclear ribonucleoproteins (snRNPs), the building blocks of spliceosomes. Here, we have identified 30 affected individuals from 22 unrelated families presenting with developmental delay, hypotonia, and cerebellar ataxia harboring biallelic variants in the GEMIN5 gene. Mutations in GEMIN5 perturb the subcellular distribution, stability, and expression of GEMIN5 protein and its interacting partners in patient iPSC-derived neurons, suggesting a potential loss-of-function mechanism. GEMIN5 mutations result in disruption of snRNP complex assembly formation in patient iPSC neurons. Furthermore, knock down of rigor mortis, the fly homolog of human GEMIN5, leads to developmental defects, motor dysfunction, and a reduced lifespan. Interestingly, we observed that GEMIN5 variants disrupt a distinct set of transcripts and pathways as compared to SMA patient neurons, suggesting different molecular pathomechanisms. These findings collectively provide evidence that pathogenic variants in GEMIN5 perturb physiological functions and result in a neurodevelopmental delay and ataxia syndrome.


Gene Expression Regulation, Developmental/genetics , Induced Pluripotent Stem Cells/metabolism , Neurodevelopmental Disorders/metabolism , Neurons/metabolism , Ribonucleoproteins, Small Nuclear/metabolism , SMN Complex Proteins/genetics , Alleles , Amino Acid Sequence , Animals , Child, Preschool , Developmental Disabilities/genetics , Drosophila/genetics , Drosophila/growth & development , Female , Gene Knockdown Techniques , Gene Ontology , HEK293 Cells , Humans , Loss of Function Mutation , Male , Muscle Hypotonia/genetics , Myoclonic Cerebellar Dyssynergia/genetics , Neurodevelopmental Disorders/diagnostic imaging , Neurodevelopmental Disorders/genetics , Neurodevelopmental Disorders/physiopathology , Pedigree , Polymorphism, Single Nucleotide , RNA-Seq , Ribonucleoproteins, Small Nuclear/genetics , Rigor Mortis/genetics , SMN Complex Proteins/metabolism
6.
Sci Rep ; 11(1): 5740, 2021 03 11.
Article En | MEDLINE | ID: mdl-33707506

In nature, photoperiod signals environmental seasonality and is a strong selective "zeitgeber" that synchronizes biological rhythms. For animals facing seasonal environmental challenges and energetic bottlenecks, daily torpor and hibernation are two metabolic strategies that can save energy. In the wild, the dwarf lemurs of Madagascar are obligate hibernators, hibernating between 3 and 7 months a year. In captivity, however, dwarf lemurs generally express torpor for periods far shorter than the hibernation season in Madagascar. We investigated whether fat-tailed dwarf lemurs (Cheirogaleus medius) housed at the Duke Lemur Center (DLC) could hibernate, by subjecting 8 individuals to husbandry conditions more in accord with those in Madagascar, including alternating photoperiods, low ambient temperatures, and food restriction. All dwarf lemurs displayed daily and multiday torpor bouts, including bouts lasting ~ 11 days. Ambient temperature was the greatest predictor of torpor bout duration, and food ingestion and night length also played a role. Unlike their wild counterparts, who rarely leave their hibernacula and do not feed during hibernation, DLC dwarf lemurs sporadically moved and ate. While demonstrating that captive dwarf lemurs are physiologically capable of hibernation, we argue that facilitating their hibernation serves both husbandry and research goals: first, it enables lemurs to express the biphasic phenotypes (fattening and fat depletion) that are characteristic of their wild conspecifics; second, by "renaturalizing" dwarf lemurs in captivity, they will emerge a better model for understanding both metabolic extremes in primates generally and metabolic disorders in humans specifically.


Cheirogaleidae/physiology , Hibernation/physiology , Animals , Feeding Behavior , Female , Linear Models , Male , North Carolina , Photoperiod , Temperature , Time Factors , Torpor/physiology , Weight Loss
7.
Appl Psychol Health Well Being ; 12(2): 288-311, 2020 07.
Article En | MEDLINE | ID: mdl-31578781

BACKGROUND: Stress and anxiety are increasingly common among young people. The current research describes two studies comparing the effects of self-selected and researcher-selected music on induced negative affect (state anxiety and physiological arousal), and state mindfulness. METHOD: In Study 1, 70 undergraduates were randomly assigned to one of three conditions: researcher-selected music, self-selected music, or a silent control condition. In Study 2, with 75 undergraduates, effects of music were compared to an active control (listening to a radio show). Negative affect was induced using a speech preparation and arithmetic task, followed by music listening or control. Self-reported anxiety and blood pressure were measured at baseline, post-induction, and post-intervention. Study 2 included state mindfulness as a dependent measure. RESULTS: Study 1 indicated that participants who listened to music (self-selected and researcher-selected) reported significantly greater anxiety reduction than participants in the silent control condition. Music did not reduce anxiety compared to an active control in Study 2. However, music listening significantly increased levels of state mindfulness, which predicted lower anxiety after self-selected music listening. CONCLUSIONS: Music may provide regulation in preparation for stressful events. Yet, the results of Study 2 indicate that other activities have similar benefits, and shows, for the first time, that music listening increases mindfulness following a stressor.


Affect , Anxiety/therapy , Auditory Perception , Choice Behavior , Mindfulness , Music Therapy , Music , Stress, Psychological/therapy , Adolescent , Adult , Affect/physiology , Anxiety/physiopathology , Auditory Perception/physiology , Choice Behavior/physiology , Female , Humans , Male , Middle Aged , Stress, Psychological/physiopathology , Treatment Outcome , Young Adult
8.
Am J Med Genet A ; 170A(5): 1115-26, 2016 May.
Article En | MEDLINE | ID: mdl-26971886

Cerebro-Costo-Mandibular syndrome (CCMS) is a rare autosomal dominant condition comprising branchial arch-derivative malformations with striking rib-gaps. Affected patients often have respiratory difficulties, associated with upper airway obstruction, reduced thoracic capacity, and scoliosis. We describe a series of 12 sporadic and 4 familial patients including 13 infants/children and 3 adults. Severe micrognathia and reduced numbers of ribs with gaps are consistent findings. Cleft palate, feeding difficulties, respiratory distress, tracheostomy requirement, and scoliosis are common. Additional malformations such as horseshoe kidney, hypospadias, and septal heart defect may occur. Microcephaly and significant developmental delay are present in a small minority of patients. Key radiological findings are of a narrow thorax, multiple posterior rib gaps and abnormal costo-transverse articulation. A novel finding in 2 patients is bilateral accessory ossicles arising from the hyoid bone. Recently, specific mutations in SNRPB, which encodes components of the major spliceosome, have been found to cause CCMS. These mutations cluster in an alternatively spliced regulatory exon and result in altered SNRPB expression. DNA was available from 14 patients and SNRPB mutations were identified in 12 (4 previously reported). Eleven had recurrent mutations previously described in patients with CCMS and one had a novel mutation in the alternative exon. These results confirm the specificity of SNRPB mutations in CCMS and provide further evidence for the role of spliceosomal proteins in craniofacial and thoracic development.


Abnormalities, Multiple/genetics , Cleft Palate/genetics , Intellectual Disability/genetics , Micrognathism/genetics , Ribs/abnormalities , snRNP Core Proteins/genetics , Abnormalities, Multiple/physiopathology , Adolescent , Child , Child, Preschool , Cleft Palate/complications , Cleft Palate/physiopathology , Exons , Female , Humans , Infant , Intellectual Disability/complications , Intellectual Disability/physiopathology , Male , Micrognathism/complications , Micrognathism/physiopathology , Mutation , Ribs/growth & development , Ribs/physiopathology , Scoliosis/complications , Scoliosis/genetics , Scoliosis/physiopathology , Spliceosomes/genetics
9.
Nat Commun ; 5: 4483, 2014 Jul 22.
Article En | MEDLINE | ID: mdl-25047197

Elucidating the function of highly conserved regulatory sequences is a significant challenge in genomics today. Certain intragenic highly conserved elements have been associated with regulating levels of core components of the spliceosome and alternative splicing of downstream genes. Here we identify mutations in one such element, a regulatory alternative exon of SNRPB as the cause of cerebro-costo-mandibular syndrome. This exon contains a premature termination codon that triggers nonsense-mediated mRNA decay when included in the transcript. These mutations cause increased inclusion of the alternative exon and decreased overall expression of SNRPB. We provide evidence for the functional importance of this conserved intragenic element in the regulation of alternative splicing and development, and suggest that the evolution of such a regulatory mechanism has contributed to the complexity of mammalian development.


Intellectual Disability/genetics , Micrognathism/genetics , Mutation , Ribs/abnormalities , snRNP Core Proteins/genetics , Alternative Splicing , Exons , Gene Expression Regulation , Humans , RNA Stability , snRNP Core Proteins/metabolism
10.
Hum Mutat ; 34(1): 97-102, 2013 Jan.
Article En | MEDLINE | ID: mdl-23033274

Acrodysostosis is characterized by nasal hypoplasia, peripheral dysostosis, variable short stature, and intellectual impairment. Recently, mutations in PRKAR1A were reported in patients with acrodysostosis and hormone resistance. Subsequently, mutations in a phosphodiesterase gene (PDE4D) were identified in seven sporadic cases. We sequenced PDE4D in seven acrodysostosis patients from five families. Missense mutations were identified in all cases. Families showed de novo inheritance except one family with three affected children whose father was subsequently found to have subtle features of acrodysostosis. There were no recurrent mutations. Short stature and endocrine resistance are rare in this series; however, cognitive involvement and obesity were frequent. This last finding is relevant given PDE4D is insulin responsive and potentially involved in lipolysis. PDE4D encodes a cyclic AMP regulator and places PDE4D-related acrodysostosis within the same family of diseases as pseudohypoparathyroidism, pseudopseudohypoparathyroidism, PRKAR1A-related acrodysostosis and brachydactyly-mental retardation syndrome; all characterized by cognitive impairment and short distal extremities.


Cyclic Nucleotide Phosphodiesterases, Type 3/genetics , Dysostoses/genetics , Genetic Predisposition to Disease/genetics , Intellectual Disability/genetics , Osteochondrodysplasias/genetics , Adult , Amino Acid Sequence , Child , Child, Preschool , Cyclic Nucleotide Phosphodiesterases, Type 3/chemistry , Cyclic Nucleotide Phosphodiesterases, Type 4 , DNA Mutational Analysis , Family Health , Female , Humans , Male , Models, Molecular , Mutation, Missense , Pedigree , Protein Structure, Tertiary
11.
Am J Hum Genet ; 90(2): 369-77, 2012 Feb 10.
Article En | MEDLINE | ID: mdl-22305528

Mandibulofacial dysostosis with microcephaly (MFDM) is a rare sporadic syndrome comprising craniofacial malformations, microcephaly, developmental delay, and a recognizable dysmorphic appearance. Major sequelae, including choanal atresia, sensorineural hearing loss, and cleft palate, each occur in a significant proportion of affected individuals. We present detailed clinical findings in 12 unrelated individuals with MFDM; these 12 individuals compose the largest reported cohort to date. To define the etiology of MFDM, we employed whole-exome sequencing of four unrelated affected individuals and identified heterozygous mutations or deletions of EFTUD2 in all four. Validation studies of eight additional individuals with MFDM demonstrated causative EFTUD2 mutations in all affected individuals tested. A range of EFTUD2-mutation types, including null alleles and frameshifts, is seen in MFDM, consistent with haploinsufficiency; segregation is de novo in all cases assessed to date. U5-116kD, the protein encoded by EFTUD2, is a highly conserved spliceosomal GTPase with a central regulatory role in catalytic splicing and post-splicing-complex disassembly. MFDM is the first multiple-malformation syndrome attributed to a defect of the major spliceosome. Our findings significantly extend the range of reported spliceosomal phenotypes in humans and pave the way for further investigation in related conditions such as Treacher Collins syndrome.


GTP Phosphohydrolases/genetics , Haploinsufficiency/genetics , Mandibulofacial Dysostosis/genetics , Microcephaly/genetics , Ribonucleoprotein, U5 Small Nuclear/genetics , Abnormalities, Multiple/genetics , Alleles , Amino Acid Sequence , Child , Child, Preschool , Cohort Studies , Exome , Female , Humans , Infant , Male , Molecular Sequence Data , Mutation/genetics , Protein Structure, Tertiary/genetics , RNA Splicing/genetics , Spliceosomes/genetics
12.
Mol Cell Biol ; 25(11): 4591-601, 2005 Jun.
Article En | MEDLINE | ID: mdl-15899862

Epithelial cells organize into cyst-like structures that contain a spherical monolayer of cells that enclose a central lumen. Using a three-dimensional basement membrane culture model in which mammary epithelial cells form hollow, acinus-like structures, we previously demonstrated that lumen formation is achieved, in part, through apoptosis of centrally localized cells. We demonstrate that the proapoptotic protein Bim may selectively trigger apoptosis of the centrally localized acinar cells, leading to temporally controlled lumen formation. Bim is not detectable during early stages of three-dimensional mammary acinar morphogenesis and is then highly upregulated in all cells of acini, coincident with detection of apoptosis in the centrally localized acinar cells. Inhibition of Bim expression by RNA interference transiently blocks luminal apoptosis and delays lumen formation. Oncogenes that induce acinar luminal filling, such as ErbB2 and v-Src, suppress expression of Bim through a pathway dependent on Erk-mitogen-activated protein kinase; however, HPV 16 E7, an oncogene that stimulates cell proliferation but not luminal filling, is unable to reduce Bim expression. Thus, Bim is a critical regulator of luminal apoptosis during mammary acinar morphogenesis in vitro and may be an important target of oncogenes that disrupt glandular epithelial architecture.


Adaptor Proteins, Signal Transducing/metabolism , Apoptosis , Genes, erbB-2/physiology , Genes, src/physiology , Mammary Glands, Human/growth & development , Oncogene Protein pp60(v-src)/metabolism , Receptor, ErbB-2/metabolism , Adaptor Proteins, Signal Transducing/genetics , Apoptosis/genetics , Apoptosis/physiology , Apoptosis Regulatory Proteins , Bcl-2-Like Protein 11 , Carrier Proteins , Cell Culture Techniques , Cell Differentiation , Cells, Cultured , Epithelial Cells/metabolism , Extracellular Signal-Regulated MAP Kinases/metabolism , Female , Humans , Mammary Glands, Human/cytology , Membrane Proteins , Morphogenesis , Mutation , Phosphorylation , Proto-Oncogene Proteins , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , RNA Interference , bcl-X Protein
13.
Cancer Res ; 65(8): 3273-80, 2005 Apr 15.
Article En | MEDLINE | ID: mdl-15833860

Ligand-induced receptor down-regulation by endocytosis is a critical process regulating the intensity and duration of receptor tyrosine kinase signaling. Ubiquitylation of specific receptor tyrosine kinases, for example, the epidermal growth factor receptor (EGFR) by the E3 ubiquitin ligase c-Cbl, provides a sorting signal for lysosomal degradation and leads to termination of receptor signaling. Cortactin, which couples the endocytic machinery to dynamic actin networks, is encoded by EMS1, a gene commonly amplified in breast and head and neck cancers. One mechanism whereby cortactin overexpression contributes to tumor progression is by enhancing tumor cell invasion and metastasis. However, in this study, we show that overexpression of cortactin in HeLa cells markedly inhibits ligand-induced down-regulation of the EGFR. This is independent of alterations in receptor autophosphorylation and correlates with impaired c-Cbl phosphorylation and association with the EGFR, reduced EGFR ubiquitylation, and sustained EGF-induced extracellular signal-regulated kinase activation. Furthermore, analysis of a panel of head and neck squamous cell carcinoma (HNSCC) cell lines revealed that cortactin overexpression is associated with attenuated ligand-induced EGFR down-regulation. Importantly, RNAi-mediated reduction of cortactin expression in an 11q13-amplified HNSCC cell line accelerates EGFR degradation. This represents the first demonstration of modulation of growth factor receptor signaling by cortactin. Moreover, enhanced EGFR signaling due to cortactin overexpression may provide an alternative explanation for EMS1 gene amplification in human cancers.


ErbB Receptors/biosynthesis , Microfilament Proteins/biosynthesis , Cortactin , Down-Regulation , ErbB Receptors/genetics , ErbB Receptors/metabolism , Extracellular Signal-Regulated MAP Kinases/metabolism , HeLa Cells , Humans , Ligands , MAP Kinase Signaling System , Microfilament Proteins/genetics , Phosphorylation , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-cbl , Transfection , Tyrosine/metabolism , Ubiquitin/metabolism , Ubiquitin-Protein Ligases/metabolism
14.
Cancer Res ; 63(15): 4322-6, 2003 Aug 01.
Article En | MEDLINE | ID: mdl-12907598

Tamoxifen, a selective estrogen-receptor modulator, is effective in the treatment and prevention of breast cancer, but therapeutic resistance is common. Pure steroidal antiestrogens are efficacious in tamoxifen-resistant disease and, unlike tamoxifen, arrest cells in a state of quiescence from which they cannot reenter the cell cycle after growth factor stimulation. We now show that in hydroxytamoxifen-treated cells, transduction of the cell cycle inhibitor p27(Kip1) induces quiescence and insensitivity to growth stimulation by insulin/insulin-like growth factor I and epidermal growth factor/transforming growth factor alpha. Furthermore, reinitiation of cell cycle progression by insulin/insulin-like growth factor I in hydroxytamoxifen-arrested cells involves dissociation of the corepressors nuclear receptor corepressor (N-CoR) and silencing mediator for retinoid and thyroid hormone receptor (SMRT) from nuclear estrogen receptor alpha and redistribution to the cytoplasm, a process that is inhibited by mitogen-activated protein/extracellular signal-regulated kinase, but not phosphatidylinositol 3'-kinase, inhibitors. These data suggest that agents that up-regulate p27(Kip1) or inhibit growth factor signaling via the extracellular signal-regulated kinases should be tested as therapeutic strategies in tamoxifen-resistant breast cancer.


Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Cell Cycle Proteins/physiology , Estradiol/analogs & derivatives , Estrogen Receptor Modulators/pharmacology , Growth Substances/pharmacology , Selective Estrogen Receptor Modulators/pharmacology , Tamoxifen/pharmacology , Tumor Suppressor Proteins/physiology , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Cell Cycle/drug effects , Cell Cycle/physiology , Cell Cycle Proteins/genetics , Cell Division/drug effects , Cell Division/physiology , Cyclin-Dependent Kinase Inhibitor p27 , DNA-Binding Proteins/metabolism , Estradiol/pharmacology , Estrogen Receptor alpha , Fulvestrant , Humans , Nuclear Proteins/metabolism , Nuclear Receptor Co-Repressor 1 , Nuclear Receptor Co-Repressor 2 , Receptors, Estrogen/metabolism , Repressor Proteins/metabolism , Tamoxifen/analogs & derivatives , Transduction, Genetic , Tumor Cells, Cultured , Tumor Suppressor Proteins/genetics
15.
Nat Cell Biol ; 5(8): 733-40, 2003 Aug.
Article En | MEDLINE | ID: mdl-12844146

Epithelial cells must adhere to the extracellular matrix (ECM) for survival, as detachment from matrix triggers apoptosis or anoikis. Integrins are major mediators of adhesion between cells and ECM proteins, and transduce signals required for cell survival. Recent evidence suggests that integrin receptors are coupled to growth factor receptors in the regulation of multiple biological functions; however, mechanisms involved in coordinate regulation of cell survival are poorly understood and mediators responsible for anoikis have not been well characterized. Here, we identify the pro-apoptotic protein Bim as a critical mediator of anoikis in epithelial cells. Bim is strongly induced after cell detachment and downregulation of Bim expression by RNA interference (RNAi) inhibits anoikis. Detachment-induced expression of Bim requires a lack of beta(1)-integrin engagement, downregulation of EGF receptor (EGFR) expression and inhibition of Erk signalling. Overexpressed EGFR was uncoupled from integrin regulation, resulting in the maintenance of Erk activation in suspension, and a block in Bim expression and anoikis. Thus, Bim functions as a key sensor of integrin and growth factor signals to the Erk pathway, and loss of such coordinate regulation may contribute to tumour progression.


Anoikis/physiology , Carrier Proteins/metabolism , ErbB Receptors/metabolism , Integrins/metabolism , Membrane Proteins , Proto-Oncogene Proteins , Animals , Apoptosis Regulatory Proteins , Bcl-2-Like Protein 11 , Carrier Proteins/genetics , Cell Fractionation , Enzyme Inhibitors/metabolism , ErbB Receptors/genetics , Extracellular Matrix/metabolism , Female , Humans , MAP Kinase Signaling System/physiology , Mice , Mice, Inbred BALB C , RNA, Small Interfering , Tumor Cells, Cultured
16.
J Biol Chem ; 278(24): 21805-13, 2003 Jun 13.
Article En | MEDLINE | ID: mdl-12672817

Growth factor regulation of the cortical actin cytoskeleton is fundamental to a wide variety of cellular processes. The cortical actin-associated protein, cortactin, regulates the formation of dynamic actin networks via the actin-related protein (Arp)2/3 complex and hence is a key mediator of such responses. In order to reveal novel roles for this versatile protein, we used a proteomics-based approach to isolate cortactin-interacting proteins. This identified several proteins, including CD2-associated protein (CD2AP), as targets for the cortactin Src homology 3 domain. Co-immunoprecipitation of CD2AP with cortactin occurred at endogenous expression levels, was transiently induced by epidermal growth factor (EGF) treatment, and required the cortactin Src homology 3 domain. The CD2AP-binding site for cortactin mapped to the second of three proline-rich regions. Because CD2AP is closely related to Cbl-interacting protein of 85 kDa (CIN85), which regulates growth factor receptor down-regulation via complex formation with Cbl and endophilin, we investigated whether the CD2AP-cortactin complex performs a similar function. EGF treatment of cells led to transient association of Cbl and the epidermal growth factor receptor (EGFR) with a constitutive CD2AP-endophilin complex. Cortactin was recruited into this complex with slightly delayed kinetics compared with Cbl and the EGFR. Immunofluorescence analysis revealed that the EGFR, CD2AP, and cortactin co-localized in regions of EGF-induced membrane ruffles. Therefore, by binding both CD2AP and the Arp2/3 complex, cortactin links receptor endocytosis to actin polymerization, which may facilitate the trafficking of internalized growth factor receptors.


Actins/metabolism , Adaptor Proteins, Signal Transducing , ErbB Receptors/metabolism , Proteins/metabolism , Actin-Related Protein 2 , Actin-Related Protein 3 , Amino Acid Sequence , Binding Sites , Blotting, Western , Carrier Proteins/chemistry , Cell Line , Cortactin , Cytoskeletal Proteins/metabolism , Cytoskeleton/metabolism , Down-Regulation , Electrophoresis, Polyacrylamide Gel , Endocytosis , Epidermal Growth Factor/metabolism , Fluorescent Antibody Technique, Indirect , Glutathione Transferase/metabolism , HeLa Cells , Humans , Immunoblotting , Kinetics , Mass Spectrometry , Microfilament Proteins/chemistry , Microscopy, Fluorescence , Models, Biological , Molecular Sequence Data , Mutagenesis, Site-Directed , Mutation , Plasmids/metabolism , Precipitin Tests , Protein Binding , Protein Structure, Tertiary , Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Sequence Homology, Amino Acid , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Transfection , Tumor Cells, Cultured , src Homology Domains
17.
EMBO J ; 21(1-2): 72-82, 2002 Jan 15.
Article En | MEDLINE | ID: mdl-11782427

Heregulin (HRG)-induced tyrosine phosphorylation of the Gab2 docking protein was enhanced by pretreatment with wortmannin, indicating negative regulation via a PI3-kinase-dependent pathway. This represents phosphorylation by the serine/threonine kinase protein kinase B (PKB), since PKB constitutively associates with Gab2, phosphorylates Gab2 on a consensus phosphorylation site, Ser159, in vitro and inhibits Gab2 tyrosine phosphorylation. However, expression of Gab2 mutated at this site (S159A Gab2) not only enhanced HRG-induced Gab2 tyrosine phosphorylation and association with Shc and ErbB2, but also markedly increased tyrosine phosphorylation of ErbB2 and other cellular proteins and amplified activation of the ERK and PKB pathways. The impact of this negative regulation was further emphasized by a potent transforming activity for S159A Gab2, but not wild-type Gab2, in fibroblasts. These studies establish Gab2 as a proto-oncogene, and a model in which receptor recruitment of Gab2 is tightly regulated via an intimate association with PKB. Release of this negative constraint enhances growth factor receptor signalling, possibly since Gab2 binding limits dephosphorylation and disassembly of receptor-associated signalling complexes.


Phosphoproteins/metabolism , Protein Serine-Threonine Kinases , Proto-Oncogene Proteins/metabolism , 3T3 Cells , Adaptor Proteins, Signal Transducing , Androstadienes/pharmacology , Animals , Binding Sites , COS Cells , Cell Line , Feedback , Humans , Mice , Mitosis , Models, Biological , Mutagenesis, Site-Directed , Neuregulin-1/metabolism , Oncogene Proteins v-erbB/metabolism , Phosphoproteins/genetics , Phosphorylation , Proto-Oncogene Mas , Proto-Oncogene Proteins c-akt , Serine/chemistry , Signal Transduction , Transfection , Wortmannin
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