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Rodríguez-Blázquez A, Carabias A, Morán-Vaquero A, de Cima S, Luque-Ortega JR, Alfonso C, Schuck P, Manso JA, Macedo-Ribeiro S, Guerrero C, de Pereda JM. Crk proteins activate the Rap1 guanine nucleotide exchange factor C3G by segregated adaptor-dependent and -independent mechanisms. Cell Commun Signal 2023; 21:30. [PMID: 36737758 PMCID: PMC9896810 DOI: 10.1186/s12964-023-01042-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 01/07/2023] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND C3G is a guanine nucleotide exchange factor (GEF) that activates Rap1 to promote cell adhesion. Resting C3G is autoinhibited and the GEF activity is released by stimuli that signal through tyrosine kinases. C3G is activated by tyrosine phosphorylation and interaction with Crk adaptor proteins, whose expression is elevated in multiple human cancers. However, the molecular details of C3G activation and the interplay between phosphorylation and Crk interaction are poorly understood. METHODS We combined biochemical, biophysical, and cell biology approaches to elucidate the mechanisms of C3G activation. Binding of Crk adaptor proteins to four proline-rich motifs (P1 to P4) in C3G was characterized in vitro using isothermal titration calorimetry and sedimentation velocity, and in Jurkat and HEK293T cells by affinity pull-down assays. The nucleotide exchange activity of C3G over Rap1 was measured using nucleotide-dissociation kinetic assays. Jurkat cells were also used to analyze C3G translocation to the plasma membrane and the C3G-dependent activation of Rap1 upon ligation of T cell receptors. RESULTS CrkL interacts through its SH3N domain with sites P1 and P2 of inactive C3G in vitro and in Jurkat and HEK293T cells, and these sites are necessary to recruit C3G to the plasma membrane. However, direct stimulation of the GEF activity requires binding of Crk proteins to the P3 and P4 sites. P3 is occluded in resting C3G and is essential for activation, while P4 contributes secondarily towards complete stimulation. Tyrosine phosphorylation of C3G alone causes marginal activation. Instead, phosphorylation primes C3G lowering the concentration of Crk proteins required for activation and increasing the maximum activity. Unexpectedly, optimal activation also requires the interaction of CrkL-SH2 domain with phosphorylated C3G. CONCLUSION Our study revealed that phosphorylation of C3G by Src and Crk-binding form a two-factor mechanism that ensures tight control of C3G activation. Additionally, the simultaneous SH2 and SH3N interaction of CrkL with C3G, required for the activation, reveals a novel adaptor-independent function of Crk proteins relevant to understanding their role in physiological signaling and their deregulation in diseases. Video abstract.
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Affiliation(s)
- Antonio Rodríguez-Blázquez
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Arturo Carabias
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007, Salamanca, Spain
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3-B, 2200, Copenhagen N, Denmark
| | - Alba Morán-Vaquero
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Sergio de Cima
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007, Salamanca, Spain
| | - Juan R Luque-Ortega
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Peter Schuck
- Laboratory of Dynamics of Macromolecular Assembly, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA
| | - José Antonio Manso
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Sandra Macedo-Ribeiro
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135, Porto, Portugal
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Carmen Guerrero
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
- Departamento de Medicina, Universidad de Salamanca, 37007, Salamanca, Spain
| | - José M de Pereda
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007, Salamanca, Spain.
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Chai S, Huang X, Wu T, Xu S, Ren W, Yang G. Comparative genomics reveals molecular mechanisms underlying health and reproduction in cryptorchid mammals. BMC Genomics 2021; 22:763. [PMID: 34702182 PMCID: PMC8547080 DOI: 10.1186/s12864-021-08084-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 10/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mammals have wide variations in testicular position, with scrotal testes in some species and ascrotal testes in others. Although cryptorchidism is hazardous to human health, some mammalian taxa are natural cryptorchids. However, the evolution of testicular position and the molecular mechanisms underlying the maintenance of health, including reproductive health, in ascrotal mammals are not clear. RESULTS In the present study, comparative genomics and evolutionary analyses revealed that genes associated with the extracellular matrix and muscle, contributing to the development of the gubernaculum, were involved in the evolution of testicular position in mammals. Moreover, genes related to testicular position were significantly associated with spermatogenesis and sperm fertility. These genes showed rapid evolution and the signature of positive selection, with specific substitutions in ascrotal mammals. Genes associated with testicular position were significantly enriched in functions and pathways related to cancer, DNA repair, DNA replication, and autophagy. CONCLUSIONS Our results revealed that alterations in gubernaculum development contributed to the evolution of testicular position in mammals and provided the first support for two hypotheses for variation in testicular position in mammals, the "cooling hypothesis", which proposes that the scrotum provides a cool environment for acutely heat-sensitive sperm and the "training hypothesis", which proposes that the scrotum develops the sperm by exposing them to an exterior environment. Further, we identified cancer resistance and DNA repair as potential protective mechanisms in natural cryptorchids. These findings provide general insights into cryptorchidism and have implications for health and infertility both in humans and domestic mammals.
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Affiliation(s)
- Simin Chai
- School of Life Sciences, Nanjing Normal University, Nanjing, 210023, Jiangsu, China
| | - Xin Huang
- School of Life Sciences, Nanjing Normal University, Nanjing, 210023, Jiangsu, China
| | - Tianzhen Wu
- School of Life Sciences, Nanjing Normal University, Nanjing, 210023, Jiangsu, China
| | - Shixia Xu
- School of Life Sciences, Nanjing Normal University, Nanjing, 210023, Jiangsu, China
| | - Wenhua Ren
- School of Life Sciences, Nanjing Normal University, Nanjing, 210023, Jiangsu, China.
| | - Guang Yang
- School of Life Sciences, Nanjing Normal University, Nanjing, 210023, Jiangsu, China.
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Sriram D, Dayma K, Devi AS, Raghawan AK, Rawat S, Radha V. Complex formation and reciprocal regulation between GSK3β and C3G. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118964. [PMID: 33450305 DOI: 10.1016/j.bbamcr.2021.118964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 11/16/2022]
Abstract
GSK3β, a ubiquitously expressed Ser/Thr kinase, regulates cell metabolism, proliferation and differentiation. Its activity is spatially and temporally regulated dependent on external stimuli and interacting partners, and its deregulation is associated with various human disorders. In this study, we identify C3G (RapGEF1), a protein essential for mammalian embryonic development as an interacting partner and substrate of GSK3β. In vivo and in vitro interaction assays demonstrated that GSK3β and Akt are present in complex with C3G. Molecular modelling and mutational analysis identified a domain in C3G that aids interaction with GSK3β, and overlaps with its nuclear export sequence. GSK3β phosphorylates C3G on primed as well as unprimed sites, and regulates its subcellular localization. Over-expression of C3G resulted in activation of Akt and inactivation of GSK3β. Huntingtin aggregate formation, dependent on GSK3β inhibition, was enhanced upon C3G overexpression. Stable clones of C2C12 cells generated by CRISPR/Cas9 mediated knockdown of C3G, that cannot differentiate, show reduced Akt activity and S9-GSK3β phosphorylation compared to wild type cells. Co-expression of catalytically active GSK3β inhibited C3G induced myocyte differentiation. C3G mutant defective for GSK3β phosphorylation, does not alter S9-GSK3β phosphorylation and, is compromised for inducing myocyte differentiation. Our results show complex formation and reciprocal regulation between GSK3β and C3G. We have identified a novel function of C3G as a negative regulator of GSK3β, a property important for its ability to induce myogenic differentiation.
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Affiliation(s)
- Divya Sriram
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Kunal Dayma
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Ambure Sharada Devi
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | | | - Shivali Rawat
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Vegesna Radha
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
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Expression of a novel brain specific isoform of C3G is regulated during development. Sci Rep 2020; 10:18838. [PMID: 33139841 PMCID: PMC7606606 DOI: 10.1038/s41598-020-75813-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022] Open
Abstract
Mice lacking C3G (RapGEF1), a ubiquitously expressed protein essential for neuronal differentiation, show multiple defects in brain development. Function of C3G in neurogenesis is poorly defined. Here, we identify brain specific expression of a novel C3G isoform in mice and humans. This isoform has an insert in the Crk-binding region, generating a polypeptide of 175 kDa, unlike the previously known 140 kDa form expressed in all other tissues. In the adult mouse brain, C3G expression is seen in neurons, but was not detectable in GFAP-positive cells. C3G levels were high in the CA3 region of hippocampus and in mitral cells of olfactory bulb. Neural progenitor cells positive for Doublecortin and Nestin, show expression of C3G. During development, C3G is expressed in precursor cells prior to their differentiation into mature neurons or astrocytes. The 175 kDa as well as 140 kDa forms are seen in embryonic mouse brain, while only the 175 kDa variant is seen in post-natal brain. Human cerebral organoids generated from induced pluripotent stem cells predominantly expressed the 140 kDa polypeptides, and the 175 kDa isoform appeared upon maturation. This study describes developmental regulation and neuronal expression of a brain specific isoform of C3G, a molecule essential for normal development of the mammalian brain.
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Carabias A, Gómez-Hernández M, de Cima S, Rodríguez-Blázquez A, Morán-Vaquero A, González-Sáenz P, Guerrero C, de Pereda JM. Mechanisms of autoregulation of C3G, activator of the GTPase Rap1, and its catalytic deregulation in lymphomas. Sci Signal 2020; 13:13/647/eabb7075. [PMID: 32873726 DOI: 10.1126/scisignal.abb7075] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
C3G is a guanine nucleotide exchange factor (GEF) that regulates cell adhesion and migration by activating the GTPase Rap1. The GEF activity of C3G is stimulated by the adaptor proteins Crk and CrkL and by tyrosine phosphorylation. Here, we uncovered mechanisms of C3G autoinhibition and activation. Specifically, we found that two intramolecular interactions regulate the activity of C3G. First, an autoinhibitory region (AIR) within the central domain of C3G binds to and blocks the catalytic Cdc25H domain. Second, the binding of the protein's N-terminal domain to its Ras exchanger motif (REM) is required for its GEF activity. CrkL activated C3G by displacing the AIR/Cdc25HD interaction. Two missense mutations in the AIR found in non-Hodgkin's lymphomas, Y554H and M555K, disrupted the autoinhibitory mechanism. Expression of C3G-Y554H or C3G-M555K in Ba/F3 pro-B cells caused constitutive activation of Rap1 and, consequently, the integrin LFA-1. Our findings suggest that sustained Rap1 activation by deregulated C3G might promote progression of lymphomas and that designing therapeutics to target C3G might treat these malignancies.
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Affiliation(s)
- Arturo Carabias
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain
| | - María Gómez-Hernández
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain
| | - Sergio de Cima
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain
| | - Antonio Rodríguez-Blázquez
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain
| | - Alba Morán-Vaquero
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain
| | - Patricia González-Sáenz
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain
| | - Carmen Guerrero
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain.,Departamento de Medicina, Facultad de Medicina, Universidad de Salamanca, Instituto de Investigación Biomédica de Salamanca (IBSAL), 37007 Salamanca, Spain
| | - José M de Pereda
- Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain.
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Gutiérrez-Herrero S, Fernández-Infante C, Hernández-Cano L, Ortiz-Rivero S, Guijas C, Martín-Granado V, González-Porras JR, Balsinde J, Porras A, Guerrero C. C3G contributes to platelet activation and aggregation by regulating major signaling pathways. Signal Transduct Target Ther 2020; 5:29. [PMID: 32296045 PMCID: PMC7109025 DOI: 10.1038/s41392-020-0119-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 01/17/2020] [Accepted: 01/18/2020] [Indexed: 01/25/2023] Open
Abstract
C3G is a GEF (guanine nucleotide exchange factor) for Rap GTPases, among which the isoform Rap1b is an essential protein in platelet biology. Using transgenic mouse models with platelet-specific overexpression of C3G or mutant C3GΔCat, we have unveiled a new function of C3G in regulating the hemostatic function of platelets through its participation in the thrombin-PKC-Rap1b pathway. C3G also plays important roles in angiogenesis, tumor growth, and metastasis through its regulation of the platelet secretome. In addition, C3G contributes to megakaryopoiesis and thrombopoiesis. Here, we used a platelet-specific C3G-KO mouse model to further support the role of C3G in hemostasis. C3G-KO platelets showed a significant delay in platelet activation and aggregation as a consequence of the defective activation of Rap1, which resulted in decreased thrombus formation in vivo. Additionally, we explored the contribution of C3G-Rap1b to platelet signaling pathways triggered by thrombin, PMA or ADP, in the referenced transgenic mouse model, through the use of a battery of specific inhibitors. We found that platelet C3G is phosphorylated at Tyr504 by a mechanism involving PKC-Src. This phosphorylation was shown to be positively regulated by ERKs through their inhibition of the tyrosine phosphatase Shp2. Moreover, C3G participates in the ADP-P2Y12-PI3K-Rap1b pathway and is a mediator of thrombin-TXA2 activities. However, it inhibits the synthesis of TXA2 through cPLA2 regulation. Taken together, our data reveal the critical role of C3G in the main pathways leading to platelet activation and aggregation through the regulation of Rap1b.
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Affiliation(s)
- Sara Gutiérrez-Herrero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
| | - Cristina Fernández-Infante
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Luis Hernández-Cano
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Sara Ortiz-Rivero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
| | - Carlos Guijas
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), University of Valladolid, Valladolid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Víctor Martín-Granado
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain
| | - José Ramón González-Porras
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
- Departamento de Hematología, Hospital Universitario de Salamanca (HUS), Salamanca, Spain
| | - Jesús Balsinde
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), University of Valladolid, Valladolid, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Almudena Porras
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Complutense University of Madrid. Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.
| | - Carmen Guerrero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), University of Salamanca-CSIC, Salamanca, Spain.
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain.
- Departamento de Medicina, University of Salamanca, Salamanca, Spain.
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Nayak SC, Radha V. C3G localizes to mother centriole dependent on cenexin, and regulates centrosome duplication and primary cilia length. J Cell Sci 2020; 133:jcs.243113. [DOI: 10.1242/jcs.243113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/06/2020] [Indexed: 01/01/2023] Open
Abstract
C3G (RapGEF1) plays a role in cell differentiation and is essential for early embryonic development in mice. In this study, we identify C3G as a centrosomal protein colocalizing with cenexin at the mother centriole in interphase cells. C3G interacts through its catalytic domain with cenexin, and they show interdependence for localization to the centrosome. C3G depletion caused a decrease in cellular cenexin levels. Centrosomal localization is lost as myocytes differentiate to form myotubes. Stable clone of cells depleted of C3G by CRISPR/Cas9 showed the presence of supernumerary centrioles. Overexpression of C3G, or a catalytically active deletion construct inhibited centrosome duplication. Cilia length is longer in C3G knockout cells, and the phenotype could be reverted upon reintroduction of C3G or its catalytic domain. Association of C3G with the basal body is dynamic, decreasing upon serum starvation, and increasing upon reentry into the cell cycle. C3G inhibits cilia formation and length dependent on its catalytic activity. We conclude that C3G inhibits centrosome duplication and maintains ciliary homeostasis, properties that may be important for its role in embryonic development.
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Affiliation(s)
- Sanjeev Chavan Nayak
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad – 500 007, India
| | - Vegesna Radha
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad – 500 007, India
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Excessive arachidonic acid induced actin bunching remodeling and podocyte injury via a PKA-c-Abl dependent pathway. Exp Cell Res 2019; 388:111808. [PMID: 31891685 DOI: 10.1016/j.yexcr.2019.111808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/17/2019] [Accepted: 12/27/2019] [Indexed: 11/22/2022]
Abstract
Recent studies have shown that serum secretory phospholipase A2 group IB (sPLA2-IB) is associated with proteinuric kidney diseases and plays a pivotal role in podocyte injury via its natural receptor. Arachidonic acid (AA), as a major metabolite of sPLA2-IB, regulates the actin bungling remodeling and contributes to the podocyte injury. However, the underlying mechanism of AA in the regulation of podocyte actin remodeling and human podocyte injury is unclear. Here, we reported that AA induced F-actin cytoskeletal ring formation and promoted protein kinase A (PKA), nephrin and c-Abl phosphorylation. Moreover, AA promoted c-Abl translocation from the nucleus to the cytoplasm and increased the recruitment of c-Abl to p-nephrin by the interaction between them. H89 (PKA inhibitor) provided protection against AA-induced F-actin bunching remodeling, down-regulated nephrin phosphorylation, and suppressed the c-Abl translocation and activation. STI571 (c-Abl inhibitor) also improved the AA associated F-actin bunching remodeling. In addition, H89 and STI571 both alleviated apoptosis and adhesion damage of podocyte. These results indicate that an excess of AA treatment is detrimental to the podocyte actin cytoskeleton and promotes podocyte injury due to the activation of PKA-c-Abl signaling.
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Nishikawa M, Nakano S, Nakao H, Sato K, Sugiyama T, Akao Y, Nagaoka H, Yamakawa H, Nagase T, Ueda H. The interaction between PLEKHG2 and ABL1 suppresses cell growth via the NF-κB signaling pathway in HEK293 cells. Cell Signal 2019; 61:93-107. [PMID: 31100317 DOI: 10.1016/j.cellsig.2019.04.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/31/2019] [Accepted: 04/01/2019] [Indexed: 01/30/2023]
Abstract
The Rho family small GTPases mediate cell responses through actin cytoskeletal rearrangement. We previously reported that PLEKHG2, a Rho-specific guanine nucleotide exchange factor, is regulated via interaction with several proteins. We found that PLEKHG2 interacted with non-receptor tyrosine kinase ABL1, but the cellular function remains unclear. Here, we show that the interaction between PLEKHG2 and ABL1 attenuated the PLEKHG2-induced serum response element-dependent gene transcription in a tyrosine phosphorylation-independent manner. PLEKHG2 and ABL1 were co-localized and accumulated within cells co-expressing PLEKHG2 and ABL1. The cellular fractionation analysis suggested that the accumulation involved actin cytoskeletal reorganization. We also revealed that the co-expression of PLEKHG2 with ABL1, but not BCR-ABL, suppressed cell growth and synergistically enhanced NF-κB-dependent gene transcription. The cell growth suppression was canceled by co-expression with IκBα, a member of the NF-κB inhibitor protein family. This study suggests that the interaction between PLEKHG2 and ABL1 suppresses cell growth through intracellular protein accumulation via the NF-κB signaling pathway.
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Affiliation(s)
- Masashi Nishikawa
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
| | - Shun Nakano
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
| | - Hiromu Nakao
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
| | - Katsuya Sato
- Department of Molecular Pathobiochemistry, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1193, Japan
| | - Tsuyoshi Sugiyama
- Department of Medical Technology, School of Health Sciences, Gifu University of Medical Science, Nagamine Ichihiraga 795-1, Seki, Gifu 501-3892, Japan
| | - Yukihiro Akao
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
| | - Hitoshi Nagaoka
- Department of Molecular Pathobiochemistry, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1193, Japan
| | | | | | - Hiroshi Ueda
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan; Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan.
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Ortiz-Rivero S, Baquero C, Hernández-Cano L, Roldán-Etcheverry JJ, Gutiérrez-Herrero S, Fernández-Infante C, Martín-Granado V, Anguita E, de Pereda JM, Porras A, Guerrero C. C3G, through its GEF activity, induces megakaryocytic differentiation and proplatelet formation. Cell Commun Signal 2018; 16:101. [PMID: 30567575 PMCID: PMC6299959 DOI: 10.1186/s12964-018-0311-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/03/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Megakaryopoiesis allows platelet formation, which is necessary for coagulation, also playing an important role in different pathologies. However, this process remains to be fully characterized. C3G, an activator of Rap1 GTPases, is involved in platelet activation and regulates several differentiation processes. METHODS We evaluated C3G function in megakaryopoiesis using transgenic mouse models where C3G and C3GΔCat (mutant lacking the GEF domain) transgenes are expressed exclusively in megakaryocytes and platelets. In addition, we used different clones of K562, HEL and DAMI cell lines with overexpression or silencing of C3G or GATA-1. RESULTS We found that C3G participates in the differentiation of immature hematopoietic cells to megakaryocytes. Accordingly, bone marrow cells from transgenic C3G, but not those from transgenic C3GΔCat mice, showed increased expression of the differentiation markers CD41 and CD61, upon thrombopoietin treatment. Furthermore, C3G overexpression increased the number of CD41+ megakaryocytes with high DNA content. These results are supported by data obtained in the different models of megakaryocytic cell lines. In addition, it was uncovered GATA-1 as a positive regulator of C3G expression. Moreover, C3G transgenic megakaryocytes from fresh bone marrow explants showed increased migration from the osteoblastic to the vascular niche and an enhanced ability to form proplatelets. Although the transgenic expression of C3G in platelets did not alter basal platelet counts, it did increase slightly those induced by TPO injection in vivo. Moreover, platelet C3G induced adipogenesis in the bone marrow under pathological conditions. CONCLUSIONS All these data indicate that C3G plays a significant role in different steps of megakaryopoiesis, acting through a mechanism dependent on its GEF activity.
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Affiliation(s)
- Sara Ortiz-Rivero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), Universidad de Salamanca-CSIC, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Cristina Baquero
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Luis Hernández-Cano
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), Universidad de Salamanca-CSIC, Salamanca, Spain
| | - Juan José Roldán-Etcheverry
- Servicio de Hematología y Hemoterapia, Hospital Clínico San Carlos, IdISSC, Departamento de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - Sara Gutiérrez-Herrero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), Universidad de Salamanca-CSIC, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Cristina Fernández-Infante
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), Universidad de Salamanca-CSIC, Salamanca, Spain
| | - Víctor Martín-Granado
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), Universidad de Salamanca-CSIC, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Eduardo Anguita
- Servicio de Hematología y Hemoterapia, Hospital Clínico San Carlos, IdISSC, Departamento de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - José María de Pereda
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), Universidad de Salamanca-CSIC, Salamanca, Spain
| | - Almudena Porras
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.
| | - Carmen Guerrero
- Instituto de Biología Molecular y Celular del Cáncer (IMBCC), Universidad de Salamanca-CSIC, Salamanca, Spain. .,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain. .,Departamento de Medicina, Universidad de Salamanca, Salamanca, Spain. .,Centro de Investigación del Cáncer, Campus Unamuno s/n, Salamanca, Spain.
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11
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Begum Z, Varalakshmi C, Sriram D, Radha V. Development and characterization of a novel monoclonal antibody that recognizes an epitope in the central protein interaction domain of RapGEF1 (C3G). Mol Biol Rep 2018; 45:1809-1819. [DOI: 10.1007/s11033-018-4327-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 08/21/2018] [Indexed: 11/29/2022]
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12
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Shakyawar DK, Dayma K, Ramadhas A, Varalakshmi C, Radha V. C3G shows regulated nucleocytoplasmic exchange and represses histone modifications associated with euchromatin. Mol Biol Cell 2017; 28:984-995. [PMID: 28148649 PMCID: PMC5385946 DOI: 10.1091/mbc.e16-09-0660] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 12/20/2022] Open
Abstract
C3G (RapGEF1), essential for mammalian embryonic development, shows dynamic nucleocytoplasmic exchange. Nuclear localization is regulated by NLSs, NES, and phosphorylation. C3G translocates to the nucleus in response to physiological stimuli and regulates chromatin modifications and gene expression. C3G (RapGEF1) is a ubiquitously expressed guanine nucleotide exchange factor that functions in signaling pathways regulating cell proliferation, apoptosis, and actin reorganization. It is essential for differentiation and early embryonic development in mice. Overexpressed C3G shows predominant cytoplasmic localization, but endogenous C3G is a component of nuclear fractions in a variety of cell types. Coexpression of importin-α and inhibition of nuclear export by leptomycin B resulted in predominant nuclear localization of C3G. Functional NLSs, NES, and GSK3-β–dependent phosphorylation regulate its dynamic nuclear localization. C3G translocates to the nucleus in response to myogenic differentiation and sublethal dose of cisplatin. C3G is associated with chromatin and nuclear matrix fractions. Cells with C3G localized in the nucleus showed peripheralization of heterochromatin and reduced histone modifications associated with euchromatin. Short hairpin RNA–mediated depletion of C3G in epithelial cells resulted in reduced expression of CDK inhibitors and the histone demethylase KDM5A. Myoblast clones with CRISPR/Cas9-mediated knockout of C3G failed to show repression of histone marks and did not show up-regulation of myosin heavy chain and myotube formation when grown in differentiation medium. Our results document regulated nucleocytoplasmic exchange of C3G in response to physiological stimuli and provide insights into nuclear functions for C3G.
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Affiliation(s)
| | - Kunal Dayma
- Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | - Anesh Ramadhas
- Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
| | | | - Vegesna Radha
- Centre for Cellular and Molecular Biology, Hyderabad 500 007, India
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13
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Rogers EM, Spracklen AJ, Bilancia CG, Sumigray KD, Allred SC, Nowotarski SH, Schaefer KN, Ritchie BJ, Peifer M. Abelson kinase acts as a robust, multifunctional scaffold in regulating embryonic morphogenesis. Mol Biol Cell 2016; 27:2613-31. [PMID: 27385341 PMCID: PMC4985262 DOI: 10.1091/mbc.e16-05-0292] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/20/2016] [Indexed: 11/16/2022] Open
Abstract
The importance of Abl kinase activity, the F-actin–binding site, and scaffolding ability in Abl’s many cell biological roles during Drosophila morphogenesis is examined. Abl is a robust multidomain scaffold with different protein motifs and activities contributing differentially to diverse cellular behaviors. Abelson family kinases (Abls) are key regulators of cell behavior and the cytoskeleton during development and in leukemia. Abl’s SH3, SH2, and tyrosine kinase domains are joined via a linker to an F-actin–binding domain (FABD). Research on Abl’s roles in cell culture led to several hypotheses for its mechanism of action: 1) Abl phosphorylates other proteins, modulating their activity, 2) Abl directly regulates the cytoskeleton via its cytoskeletal interaction domains, and/or 3) Abl is a scaffold for a signaling complex. The importance of these roles during normal development remains untested. We tested these mechanistic hypotheses during Drosophila morphogenesis using a series of mutants to examine Abl’s many cell biological roles. Strikingly, Abl lacking the FABD fully rescued morphogenesis, cell shape change, actin regulation, and viability, whereas kinase-dead Abl, although reduced in function, retained substantial rescuing ability in some but not all Abl functions. We also tested the function of four conserved motifs in the linker region, revealing a key role for a conserved PXXP motif known to bind Crk and Abi. We propose that Abl acts as a robust multidomain scaffold with different protein motifs and activities contributing differentially to diverse cellular behaviors.
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Affiliation(s)
- Edward M Rogers
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Andrew J Spracklen
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Colleen G Bilancia
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kaelyn D Sumigray
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - S Colby Allred
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Stephanie H Nowotarski
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kristina N Schaefer
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Benjamin J Ritchie
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Mark Peifer
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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14
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Yang Q, Ma Y, Liu Y, Liang W, Chen X, Ren Z, Wang H, Singhal PC, Ding G. Angiotensin II down-regulates nephrin-Akt signaling and induces podocyte injury: roleof c-Abl. Mol Biol Cell 2015; 27:197-208. [PMID: 26510503 PMCID: PMC4694757 DOI: 10.1091/mbc.e15-04-0223] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 10/23/2015] [Indexed: 11/17/2022] Open
Abstract
Ang II plays a vital role in the initiation and progression of proteinuric kidney diseases, but the mechanism is still elusive. It is shown that c-Abl is a molecular chaperone of nephrin signaling and the SHIP2-Akt pathway, and released c-Abl from nephrin is involved in Ang II–induced podocyte injury. Recent studies have shown that nephrin plays a vital role in angiotensin II (Ang II)–induced podocyte injury and thus contributes to the onset of proteinuria and the progression of renal diseases, but its specific mechanism remains unclear. c-Abl is an SH2/SH3 domain–containing nonreceptor tyrosine kinase that is involved in cell survival and regulation of the cytoskeleton. Phosphorylated nephrin is able to interact with molecules containing SH2/SH3 domains, suggesting that c-Abl may be a downstream molecule of nephrin signaling. Here we report that Ang II–infused rats developed proteinuria and podocyte damage accompanied by nephrin dephosphorylation and minimal interaction between nephrin and c-Abl. In vitro, Ang II induced podocyte injury and nephrin and Akt dephosphorylation, which occurred in tandem with minimal interaction between nephrin and c-Abl. Moreover, Ang II promoted c-Abl phosphorylation and interaction between c-Abl and SH2 domain–containing 5′-inositol phosphatase 2 (SHIP2). c-Abl small interfering RNA (siRNA) and STI571 (c-Abl inhibitor) provided protection against Ang II–induced podocyte injury, suppressed the Ang II-induced c-Abl–SHIP2 interaction and SHIP2 phosphorylation, and maintained a stable level of nephrin phosphorylation. These results indicate that c-Abl is a molecular chaperone of nephrin signaling and the SHIP2-Akt pathway and that the released c-Abl contributes to Ang II–induced podocyte injury.
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Affiliation(s)
- Qian Yang
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Yiqiong Ma
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Yipeng Liu
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Wei Liang
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Xinghua Chen
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Zhilong Ren
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Huiming Wang
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
| | - Pravin C Singhal
- Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore-Long Island Medical School, Great Neck, NY 11021
| | - Guohua Ding
- Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China
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15
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Sasi Kumar K, Ramadhas A, Nayak S, Kaniyappan S, Dayma K, Radha V. C3G (RapGEF1), a regulator of actin dynamics promotes survival and myogenic differentiation of mouse mesenchymal cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2629-39. [DOI: 10.1016/j.bbamcr.2015.06.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/17/2015] [Accepted: 06/27/2015] [Indexed: 12/11/2022]
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16
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Dayma K, Ramadhas A, Sasikumar K, Radha V. Reciprocal Negative Regulation between the Guanine Nucleotide Exchange Factor C3G and β-Catenin. Genes Cancer 2013; 3:564-77. [PMID: 23486661 DOI: 10.1177/1947601912471189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 11/15/2012] [Indexed: 11/15/2022] Open
Abstract
The guanine nucleotide exchange factor C3G (RAPGEF1) regulates proliferation, migration, and differentiation of cells and is essential for mammalian embryonic development. The molecular effectors of C3G dependent functions are poorly understood. Here we report that C3G functions as a negative regulator of β-catenin, a major player in pathways known to be deregulated in human cancers. In mammalian cells, C3G is present in a complex with cellular β-catenin. The proline rich Crk binding region of C3G and residues 90-525 of β-catenin are sufficient for the interaction. Knockdown of cellular C3G stimulated, and its overexpression repressed, β-catenin/TCF transcription activity. C3G acts by destabilizing β-catenin protein and inhibiting its nuclear accumulation. Nuclear extracts of C3G overexpressing cells showed reduced binding to TCF consensus oligos. C3G exerts its effects independent of its function as an exchange factor. It also inhibits stability and activity of an N-terminal deletion construct of β-catenin that is not subject to GSK3β dependent phosphorylation, suggesting that C3G exerts its effect independent of GSK3β. β-catenin repression by C3G was not significantly altered in the presence of proteasome inhibitors, MG132 or lactacystin, suggesting that alternate mechanisms are engaged by C3G to cause β-catenin turnover. C3G expression represses β-catenin target gene expression, and stable clones of MCF-7 breast cancer cells expressing C3G showed reduced migration. Activation of cellular β-catenin or expression of constitutively active β-catenin resulted in reduced C3G expression, indicating that C3G gene expression is negatively regulated by β-catenin. Our results identify a novel property of C3G in functioning as a negative regulator of β-catenin signaling by promoting its degradation. In addition, we show that β-catenin inhibits C3G expression, forming a feedback loop.
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Affiliation(s)
- Kunal Dayma
- Centre for Cellular and Molecular Biology, Hyderabad, India
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17
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Li C, Beck B, Su B, Terhune J, Peatman E. Early mucosal responses in blue catfish (Ictalurus furcatus) skin to Aeromonas hydrophila infection. FISH & SHELLFISH IMMUNOLOGY 2013; 34:920-928. [PMID: 23337110 DOI: 10.1016/j.fsi.2013.01.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 12/27/2012] [Accepted: 01/04/2013] [Indexed: 06/01/2023]
Abstract
Bacterial pathogens are well-equipped to detect, adhere to, and initiate infection in their finfish hosts. The mucosal surfaces of fish, such as the skin, function as the front line of defense against such bacterial insults that are routinely encountered in the aquatic environment. While recent progress has been made, and despite the obvious importance of mucosal surfaces, the precise molecular events that occur soon after encountering bacterial pathogens remain unclear. Indeed, these early events are critical in mounting appropriate responses that ultimately determine host survival or death. In the present study, we investigated the transcriptional consequences of a virulent Aeromonas hydrophila challenge in the skin of blue catfish, Ictalurus furcatus. We utilized an 8×60K Agilent microarray to examine gene expression profiles at key early timepoints following challenge (2 h, 12 h, and 24 h). A total of 1155 unique genes were significantly altered during at least one timepoint. We observed dysregulation in a number of genes involved in diverse pathways including those involved in antioxidant responses, apoptosis, cytoskeletal rearrangement, immunity, and extracellular matrix protein diversity and regulation. Taken together, A. hydrophila coordinately modulates mucosal factors across numerous cellular pathways in a manner predicted to enhance its ability to adhere to and infect the blue catfish host.
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Affiliation(s)
- Chao Li
- Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, AL 36849, USA
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18
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Maia V, Ortiz-Rivero S, Sanz M, Gutierrez-Berzal J, Alvarez-Fernández I, Gutierrez-Herrero S, de Pereda JM, Porras A, Guerrero C. C3G forms complexes with Bcr-Abl and p38α MAPK at the focal adhesions in chronic myeloid leukemia cells: implication in the regulation of leukemic cell adhesion. Cell Commun Signal 2013; 11:9. [PMID: 23343344 PMCID: PMC3629710 DOI: 10.1186/1478-811x-11-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 01/18/2013] [Indexed: 12/17/2022] Open
Abstract
Background Previous studies by our group and others have shown that C3G interacts with Bcr-Abl through its SH3-b domain. Results In this work we show that C3G and Bcr-Abl form complexes with the focal adhesion (FA) proteins CrkL, p130Cas, Cbl and Abi1 through SH3/SH3-b interactions. The association between C3G and Bcr-Abl decreased upon Abi1 or p130Cas knock-down in K562 cells, which suggests that Abi1 and p130Cas are essential partners in this interaction. On the other hand, C3G, Abi1 or Cbl knock-down impaired adhesion to fibronectin, while p130Cas silencing enhanced it. C3G, Cbl and p130Cas-SH3-b domains interact directly with common proteins involved in the regulation of cell adhesion and migration. Immunoprecipitation and immunofluorescence studies revealed that C3G form complexes with the FA proteins paxillin and FAK and their phosphorylated forms. Additionally, C3G, Abi1, Cbl and p130Cas regulate the expression and phosphorylation of paxillin and FAK. p38α MAPK also participates in the regulation of adhesion in chronic myeloid leukemia cells. It interacts with C3G, CrkL, FAK and paxillin and regulates the expression of paxillin, CrkL and α5 integrin, as well as paxillin phosphorylation. Moreover, double knock-down of C3G/p38α decreased adhesion to fibronectin, similarly to the single silencing of one of these genes, either C3G or p38α. These suggest that C3G and p38α MAPK are acting through a common pathway to regulate cell adhesion in K562 cells, as previously described for the regulation of apoptosis. Conclusions Our results indicate that C3G-p38αMAPK pathway regulates K562 cell adhesion through the interaction with FA proteins and Bcr-Abl, modulating the formation of different protein complexes at FA.
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Affiliation(s)
- Vera Maia
- Centro de Investigación del Cáncer, IBMCC, CSIC-Universidad de Salamanca, Salamanca, Spain.
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The tyrosine phosphatase TC48 interacts with and inactivates the oncogenic fusion protein BCR-Abl but not cellular Abl. Biochim Biophys Acta Mol Basis Dis 2012; 1832:275-84. [PMID: 23124138 DOI: 10.1016/j.bbadis.2012.10.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 10/25/2012] [Accepted: 10/26/2012] [Indexed: 11/20/2022]
Abstract
The chimeric oncoprotein BCR-Abl exhibits deregulated protein tyrosine kinase activity and is responsible for the pathogenesis of certain human leukemias, such as chronic myelogenous leukemia. The activities of cellular Abl (c-Abl) and BCR-Abl are stringently regulated and the cellular mechanisms involved in their inactivation are poorly understood. Protein tyrosine phosphatases can negatively regulate Abl mediated signaling by dephosphorylating the kinase and/or its substrates. This study investigated the ability of the intracellular T cell protein tyrosine phosphatase (TCPTP/PTPN2) to dephosphorylate and regulate the functions of BCR-Abl and c-Abl. TCPTP is expressed as two alternately spliced isoforms - TC48 and TC45, which differ in their C-termini and localize to the cytoplasm and nucleus respectively. We show that TC48 dephosphorylates BCR-Abl but not c-Abl and inhibits its activity towards its substrate, CrkII. Y1127 and Y1294 residues whose phosphorylation corresponds with BCR-Abl activation status were the primary sites targeted by TC48. Co-localization and immunoprecipitation experiments showed that TC48 interacted with BCR-Abl but not with c-Abl, and BCR domain was sufficient for interaction. TC48 expression resulted in the stabilization of Bcr-Abl protein dependent on its phosphatase activity. Inactivation of cellular TC48 in K562 cells by stable expression of a dominant negative catalytically inactive mutant TC48, enhanced proliferation. TC48 expressing K562 clones showed reduced proliferation and enhanced sensitivity to STI571 compared to control clones suggesting that TC48 can repress the growth of CML cells. This study identifies a novel cellular regulator that specifically inhibits the activity of oncogenic BCR-Abl but not that of the cellular Abl kinase.
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Regulation of adherens junction dynamics by phosphorylation switches. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:125295. [PMID: 22848810 PMCID: PMC3403498 DOI: 10.1155/2012/125295] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 12/15/2022]
Abstract
Adherens junctions connect the actin cytoskeleton of neighboring cells through transmembrane cadherin receptors and a network of adaptor proteins. The interactions between these adaptors and cadherin as well as the activity of actin regulators localized to adherens junctions are tightly controlled to facilitate cell junction assembly or disassembly in response to changes in external or internal forces and/or signaling. Phosphorylation of tyrosine, serine, or threonine residues acts as a switch on the majority of adherens junction proteins, turning "on" or "off" their interactions with other proteins and/or their enzymatic activity. Here, we provide an overview of the kinases and phosphatases regulating phosphorylation of adherens junction proteins and bring examples of phosphorylation events leading to the assembly or disassembly of adherens junctions, highlighting the important role of phosphorylation switches in regulating their dynamics.
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Constance JE, Despres SD, Nishida A, Lim CS. Selective targeting of c-Abl via a cryptic mitochondrial targeting signal activated by cellular redox status in leukemic and breast cancer cells. Pharm Res 2012; 29:2317-28. [PMID: 22549737 DOI: 10.1007/s11095-012-0758-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 04/11/2012] [Indexed: 01/03/2023]
Abstract
PURPOSE The tyrosine kinase c-Abl localizes to the mitochondria under cell stress conditions and promotes apoptosis. However, c-Abl has not been directly targeted to the mitochondria. Fusing c-Abl to a mitochondrial translocation signal (MTS) that is activated by reactive oxygen species (ROS) will selectively target the mitochondria of cancer cells exhibiting an elevated ROS phenotype. Mitochondrially targeted c-Abl will thereby induce malignant cell death. METHODS Confocal microscopy was used to determine mitochondrial colocalization of ectopically expressed c-Abl-EGFP/cMTS fusion across three cell lines (K562, Cos-7, and 1471.1) with varying levels of basal (and pharmacologically modulated) ROS. ROS were quantified by indicator dye assay. The functional consequences of mitochondrial c-Abl were assessed by DNA accessibility to 7-AAD using flow cytometry. RESULTS The cMTS and cMTS/c-Abl fusions colocalized to the mitochondria in leukemic (K562) and breast (1471.1) cancer phenotypes (but not Cos-7 fibroblasts) in a ROS and PKC dependent manner. CONCLUSIONS We confirm and extend oxidative stress activated translocation of the cMTS by demonstrating that the cMTS and Abl/cMTS fusion selectively target the mitochondria of K562 leukemia and mammary adenocarcinoma 1471.1 cells. c-Abl induced K562 leukemia cell death when targeted to the matrix but not the outer membrane of the mitochondria.
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Affiliation(s)
- Jonathan E Constance
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108, USA.
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22
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Mitra A, Kalayarasan S, Gupta V, Radha V. TC-PTP dephosphorylates the guanine nucleotide exchange factor C3G (RapGEF1) and negatively regulates differentiation of human neuroblastoma cells. PLoS One 2011; 6:e23681. [PMID: 21876762 PMCID: PMC3158094 DOI: 10.1371/journal.pone.0023681] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 07/24/2011] [Indexed: 11/29/2022] Open
Abstract
The guanine nucleotide exchange factor, C3G (RapGEF1), functions in multiple signaling pathways involved in cell adhesion, proliferation, apoptosis and actin reorganization. C3G is regulated by tyrosine phosphorylation on Y504, known to be mediated by c-Abl and Src family kinases. In the present study we explored the possibility of cellular phospho-C3G (pC3G) being a substrate of the intracellular T-cell protein tyrosine phosphatase TC-PTP (PTPN2) using the human neuroblastoma cell line, IMR-32. In vivo and in vitro binding assays demonstrated interaction between C3G and TC-PTP. Interaction is mediated through the Crk-binding region of C3G and C-terminal noncatalytic residues of TC-PTP. C3G interacted better with a substrate trap mutant of TC48 and this complex formation was inhibited by vanadate. Endogenous pC3G colocalized with catalytically inactive mutant TC48 in the Golgi. Expression of TC48 abrogated pervanadate and c-Src induced phosphorylation of C3G without affecting total cellular phospho-tyrosine. Insulin-like growth factor treatment of c-Src expressing cells resulted in dephosphorylation of C3G dependent on the activity of endogenous TC48. TC48 expression inhibited forskolin induced tyrosine phosphorylation of C3G and neurite outgrowth in IMR-32 cells. Our results identify a novel Golgi localized substrate of TC48 and delineate a role for TC48 in dephosphorylation of substrates required during differentiation of human neuroblastoma cells.
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Affiliation(s)
- Aninda Mitra
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, Andhra Pradesh, India
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Signalling to actin: role of C3G, a multitasking guanine-nucleotide-exchange factor. Biosci Rep 2011; 31:231-44. [PMID: 21366540 DOI: 10.1042/bsr20100094] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
C3G (Crk SH3-domain-binding guanine-nucleotide-releasing factor) is a ubiquitously expressed member of a class of molecules called GEFs (guanine-nucleotide-exchange factor) that activate small GTPases and is involved in pathways triggered by a variety of signals. It is essential for mammalian embryonic development and many cellular functions in adult tissues. C3G participates in regulating functions that require cytoskeletal remodelling such as adhesion, migration, maintenance of cell junctions, neurite growth and vesicle traffic. C3G is spatially and temporally regulated to act on Ras family GTPases Rap1, Rap2, R-Ras, TC21 and Rho family member TC10. Increased C3G protein levels are associated with differentiation of various cell types, indicating an important role for C3G in cellular differentiation. In signalling pathways, C3G serves functions dependent on catalytic activity as well as protein interaction and can therefore integrate signals necessary for the execution of more than one cellular function. This review summarizes our current knowledge of the biology of C3G with emphasis on its role as a transducer of signals to the actin cytoskeleton. Deregulated C3G may also contribute to pathogenesis of human disorders and therefore could be a potential therapeutic target.
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Cytoskeletal remodeling by C3G to induce neurite-like extensions and inhibit motility in highly invasive breast carcinoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:456-65. [DOI: 10.1016/j.bbamcr.2011.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 12/29/2010] [Accepted: 01/03/2011] [Indexed: 11/24/2022]
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