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Chen XY, Cheng AY, Wang ZY, Jin JM, Lin JY, Wang B, Guan YY, Zhang H, Jiang YX, Luan X, Zhang LJ. Dbl family RhoGEFs in cancer: different roles and targeting strategies. Biochem Pharmacol 2024; 223:116141. [PMID: 38499108 DOI: 10.1016/j.bcp.2024.116141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/06/2024] [Accepted: 03/15/2024] [Indexed: 03/20/2024]
Abstract
Small Ras homologous guanosine triphosphatase (Rho GTPase) family proteins are highly associated with tumorigenesis and development. As intrinsic exchange activity regulators of Rho GTPases, Rho guanine nucleotide exchange factors (RhoGEFs) have been demonstrated to be closely involved in tumor development and received increasing attention. They mainly contain two families: the diffuse B-cell lymphoma (Dbl) family and the dedicator of cytokinesis (Dock) family. More and more emphasis has been paid to the Dbl family members for their abnormally high expression in various cancers and their correlation to poor prognosis. In this review, the common and distinctive structures of Dbl family members are discussed, and their roles in cancer are summarized with a focus on Ect2, Tiam1/2, P-Rex1/2, Vav1/2/3, Trio, KALRN, and LARG. Significantly, the strategies targeting Dbl family RhoGEFs are highlighted as novel therapeutic opportunities for cancer.
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Affiliation(s)
- Xin-Yi Chen
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Ao-Yu Cheng
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Zi-Ying Wang
- School of Biological Engineering, Tianjin University of Science&Technology, Tianjin 301617, China
| | - Jin-Mei Jin
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Jia-Yi Lin
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Bei Wang
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Ying-Yun Guan
- Department of Pharmacy, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China
| | - Hao Zhang
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yi-Xin Jiang
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
| | - Xin Luan
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
| | - Li-Jun Zhang
- Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
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Ravala SK, Adame-Garcia SR, Li S, Chen CL, Cianfrocco MA, Gutkind JS, Cash JN, Tesmer JJG. Structural and dynamic changes in P-Rex1 upon activation by PIP 3 and inhibition by IP 4. bioRxiv 2024:2023.09.15.557836. [PMID: 37745379 PMCID: PMC10515948 DOI: 10.1101/2023.09.15.557836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
PIP3-dependent Rac exchanger 1 (P-Rex1) is abundantly expressed in neutrophils and plays central roles in chemotaxis and cancer metastasis by serving as a guanine-nucleotide exchange factor (GEF) for Rac. The enzyme is synergistically activated by PIP3 and the heterotrimeric Gβγ subunits, but mechanistic details remain poorly understood. While investigating the regulation of P-Rex1 by PIP3, we discovered that Ins(1,3,4,5)P4 (IP4) inhibits P-Rex1 activity and induces large decreases in backbone dynamics in diverse regions of the protein. Cryo-electron microscopy analysis of the P-Rex1·IP4 complex revealed a conformation wherein the pleckstrin homology (PH) domain occludes the active site of the Dbl homology (DH) domain. This configuration is stabilized by interactions between the first DEP domain (DEP1) and the DH domain and between the PH domain and a 4-helix bundle (4HB) subdomain that extends from the C-terminal domain of P-Rex1. Disruption of the DH-DEP1 interface in a DH/PH-DEP1 fragment enhanced activity and led to a more extended conformation in solution, whereas mutations that constrain the occluded conformation led to decreased GEF activity. Variants of full-length P-Rex1 in which the DH-DEP1 and PH-4HB interfaces were disturbed exhibited enhanced activity during chemokine-induced cell migration, confirming that the observed structure represents the autoinhibited state in living cells. Interactions with PIP3-containing liposomes led to disruption of these interfaces and increased dynamics protein-wide. Our results further suggest that inositol phosphates such as IP4 help to inhibit basal P-Rex1 activity in neutrophils, similar to their inhibitory effects on phosphatidylinositol-3-kinase.
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Affiliation(s)
- Sandeep K. Ravala
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| | - Sendi Rafael Adame-Garcia
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, San Diego, CA 92093, USA
| | - Sheng Li
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Chun-Liang Chen
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| | - Michael A. Cianfrocco
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - J. Silvio Gutkind
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, San Diego, CA 92093, USA
| | - Jennifer N. Cash
- Department of Molecular and Cellular Biology, University of California-Davis, Davis, CA, 95616, USA
| | - John J. G. Tesmer
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
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Zhang M, Ding Y, Hu S, Li F, Wang Y, Zhou Y, Qi M, Ni H, Fang S, Chen Q. Transcriptomics and systems network-based molecular mechanism of herbal formula Huosu-Yangwei inhibited gastric cancer in vivo. J Ethnopharmacol 2023:116674. [PMID: 37277085 DOI: 10.1016/j.jep.2023.116674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/08/2023] [Accepted: 05/21/2023] [Indexed: 06/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The efficacy of the herbal formula Huosu-Yangwei (HSYW) in the treatment of advanced gastric cancer and chronic atrophic gastritis with precancerous lesions has been reported in clinical trials. However, the molecular mechanisms underlying its inhibition of gastric tumor are not well-understood. AIM OF THE STUDY Combined with transcriptomics and systems network-based molecular mechanism to explore the potential circRNA-miRNA-mRNA network of HSYW in the treatment of gastric cancer. MATERIALS AND METHODS Animal experiments were conducted to investigate the effect of HSYW on tumor growth in vivo. RNA sequencing (RNA-seq) was implemented to identify the differentially expressed (DE) genes. Predictive miRNA targets and mRNA were used to construct circRNA-miRNA-mRNA networks and protein-protein interaction (PPI) networks. Quantitative real-time PCR (qRT-PCR) was utilized to verify the accuracy of the proposed circRNA-miRNA-mRNA networks. Additionally, the differentially expressed target proteins between gastric cancer (GC) and normal patients were assessed using data from the TCGA (The Cancer Genome Atlas) and HPA (The Human Protein Atlas) databases. RESULTS We demonstrate HSYW significantly inhibits tumor growth of N87 cell-bearing Balb/c mice. Transcriptomic analysis revealed the existence of 119 differentially expressed (DE) circRNAs and 200 DE mRNAs between HSYW-treated and model mice. By associating predicted circRNA-miRNA pairs and miRNA-mRNA pairs, we constructed a circRNA-miRNA-mRNA (CMM) network. Furthermore, a protein-protein interaction (PPI) network was developed using the differential expressed mRNAs. Consequently, the reconstructed core CMM network and qRT-PCR validation indicated that 4 circRNAs, 5 miRNAs and 6 mRNAs could potentially serve as biomarkers to assess the therapeutic effects of HSYW-treated N87-bearing Balb/c mice. The TCGA and HPA databases also demonstrated that mRNA KLF15 and PREX1 had substantial differences between gastric cancer (GC) and healthy controls. CONCLUSIONS By combining the experimental and bioinformatics analysis, this study confirms that the circRNA_00240/hsa-miR-642a-5p/KLF15 and circRNA_07980/hsa-miR-766-3p/PREX1 pathways play critical roles in HSYW-treated gastric cancer.
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Affiliation(s)
- Mengyuan Zhang
- Department of Gastroenterology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China
| | - Yujie Ding
- School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Sheng Hu
- Central Laboratory, Shanghai Skin Disease Hospital, School of Medicine, Tongji University, Shanghai, 200443, China
| | - Fulong Li
- Department of Gastroenterology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China
| | - Yi Wang
- Department of Gastroenterology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China
| | - Yue Zhou
- Department of Gastroenterology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China
| | - Mei Qi
- Department of Gastroenterology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China
| | - HongMei Ni
- School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
| | - Shengquan Fang
- Department of Gastroenterology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China.
| | - Qilong Chen
- Central Laboratory, Shanghai Skin Disease Hospital, School of Medicine, Tongji University, Shanghai, 200443, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, 200120, China.
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4
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Rivera M, Toledo-Jacobo L, Romero E, Oprea TI, Moses ME, Hudson LG, Wandinger-Ness A, Grimes MM. Agent-based modeling predicts RAC1 is critical for ovarian cancer metastasis. Mol Biol Cell 2022; 33:ar138. [PMID: 36200848 PMCID: PMC9727804 DOI: 10.1091/mbc.e21-11-0540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Experimental and computational studies pinpoint rate-limiting step(s) in metastasis governed by Rac1. Using ovarian cancer cell and animal models, Rac1 expression was manipulated, and quantitative measurements of cell-cell and cell-substrate adhesion, cell invasion, mesothelial clearance, and peritoneal tumor growth discriminated the tumor behaviors most highly influenced by Rac1. The experimental data were used to parameterize an agent-based computational model simulating peritoneal niche colonization, intravasation, and hematogenous metastasis to distant organs. Increased ovarian cancer cell survival afforded by the more rapid adhesion and intravasation upon Rac1 overexpression is predicted to increase the numbers of and the rates at which tumor cells are disseminated to distant sites. Surprisingly, crowding of cancer cells along the blood vessel was found to decrease the numbers of cells reaching a distant niche irrespective of Rac1 overexpression or knockdown, suggesting that sites for tumor cell intravasation are rate limiting and become accessible if cells intravasate rapidly or are displaced due to diminished viability. Modeling predictions were confirmed through animal studies of Rac1-dependent metastasis to the lung. Collectively, the experimental and modeling approaches identify cell adhesion, rapid intravasation, and survival in the blood as parameters in the ovarian metastatic cascade that are most critically dependent on Rac1.
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Affiliation(s)
- Melanie Rivera
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Leslie Toledo-Jacobo
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Elsa Romero
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Tudor I. Oprea
- Division of Translational Informatics, Department of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131,Translational Informatics, Roivant Discovery, Boston, MA 02210
| | - Melanie E. Moses
- Department of Computer Science, University of New Mexico, Albuquerque, NM 87131
| | - Laurie G. Hudson
- Cancer Research Facility, Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131,Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
| | - Angela Wandinger-Ness
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131,Cancer Research Facility, Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131,*Address correspondence to: Angela Wandinger-Ness ()
| | - Martha M. Grimes
- Cancer Research Facility, Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131,Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131
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5
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Chang YG, Lupton CJ, Bayly-Jones C, Keen AC, D'Andrea L, Lucato CM, Steele JR, Venugopal H, Schittenhelm RB, Whisstock JC, Halls ML, Ellisdon AM. Structure of the metastatic factor P-Rex1 reveals a two-layered autoinhibitory mechanism. Nat Struct Mol Biol 2022. [PMID: 35864164 DOI: 10.1038/s41594-022-00804-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/09/2022] [Indexed: 11/08/2022]
Abstract
P-Rex (PI(3,4,5)P3-dependent Rac exchanger) guanine nucleotide exchange factors potently activate Rho GTPases. P-Rex guanine nucleotide exchange factors are autoinhibited, synergistically activated by Gβγ and PI(3,4,5)P3 binding and dysregulated in cancer. Here, we use X-ray crystallography, cryogenic electron microscopy and crosslinking mass spectrometry to determine the structural basis of human P-Rex1 autoinhibition. P-Rex1 has a bipartite structure of N- and C-terminal modules connected by a C-terminal four-helix bundle that binds the N-terminal Pleckstrin homology (PH) domain. In the N-terminal module, the Dbl homology (DH) domain catalytic surface is occluded by the compact arrangement of the DH-PH-DEP1 domains. Structural analysis reveals a remarkable conformational transition to release autoinhibition, requiring a 126° opening of the DH domain hinge helix. The off-axis position of Gβγ and PI(3,4,5)P3 binding sites further suggests a counter-rotation of the P-Rex1 halves by 90° facilitates PH domain uncoupling from the four-helix bundle, releasing the autoinhibited DH domain to drive Rho GTPase signaling. Cryo-EM, X-ray crystallography and crosslinking mass spectrometry are harnessed to solve the structure of the full-length Rho-GEF P-Rex1, uncovering a two-layered mechanism of autoinhibition released upon Gβγ and PI(3,4,5)P3 binding.
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6
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Lawson CD, Hornigold K, Pan D, Niewczas I, Andrews S, Clark J, Welch HCE. Small-molecule inhibitors of P-Rex guanine-nucleotide exchange factors. Small GTPases 2022; 13:307-326. [PMID: 36342857 PMCID: PMC9645260 DOI: 10.1080/21541248.2022.2131313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
P-Rex1 and P-Rex2 are guanine-nucleotide exchange factors (GEFs) that activate Rac small GTPases in response to the stimulation of G protein-coupled receptors and phosphoinositide 3-kinase. P-Rex Rac-GEFs regulate the morphology, adhesion and migration of various cell types, as well as reactive oxygen species production and cell cycle progression. P-Rex Rac-GEFs also have pathogenic roles in the initiation, progression or metastasis of several types of cancer. With one exception, all P-Rex functions are known or assumed to be mediated through their catalytic Rac-GEF activity. Thus, inhibitors of P-Rex Rac-GEF activity would be valuable research tools. We have generated a panel of small-molecule P-Rex inhibitors that target the interface between the catalytic DH domain of P-Rex Rac-GEFs and Rac. Our best-characterized compound, P-Rex inhibitor 1 (PREX-in1), blocks the Rac-GEF activity of full-length P-Rex1 and P-Rex2, and of their isolated catalytic domains, in vitro at low-micromolar concentration, without affecting the activities of several other Rho-GEFs. PREX-in1 blocks the P-Rex1 dependent spreading of PDGF-stimulated endothelial cells and the production of reactive oxygen species in fMLP-stimulated mouse neutrophils. Structure-function analysis revealed critical structural elements of PREX-in1, allowing us to develop derivatives with increased efficacy, the best with an IC50 of 2 µM. In summary, we have developed PREX-in1 and derivative small-molecule compounds that will be useful laboratory research tools for the study of P-Rex function. These compounds may also be a good starting point for the future development of more sophisticated drug-like inhibitors aimed at targeting P-Rex Rac-GEFs in cancer.
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Affiliation(s)
- CD Lawson
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - K Hornigold
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - D Pan
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - I Niewczas
- Biological Chemistry Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - S Andrews
- Bioinformatics Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - J Clark
- Biological Chemistry Facility, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK
| | - HCE Welch
- Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3AT, UK,CONTACT HCE Welch Signalling Programme, The Babraham Institute, Babraham Research Campus, CambridgeCB22 3ATUK
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7
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Lavictoire SJ, Jomaa D, Gont A, Jardine K, Cook DP, Lorimer IAJ. Identification of Rac guanine nucleotide exchange factors promoting Lgl1 phosphorylation in glioblastoma. J Biol Chem 2021; 297:101172. [PMID: 34624316 PMCID: PMC8551657 DOI: 10.1016/j.jbc.2021.101172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 08/25/2021] [Accepted: 09/03/2021] [Indexed: 11/23/2022] Open
Abstract
The protein Lgl1 is a key regulator of cell polarity. We previously showed that Lgl1 is inactivated by hyperphosphorylation in glioblastoma as a consequence of PTEN tumour suppressor loss and aberrant activation of the PI 3-kinase pathway; this contributes to glioblastoma pathogenesis both by promoting invasion and repressing glioblastoma cell differentiation. Lgl1 is phosphorylated by atypical protein kinase C that has been activated by binding to a complex of the scaffolding protein Par6 and active, GTP-bound Rac. The specific Rac guanine nucleotide exchange factors that generate active Rac to promote Lgl1 hyperphosphorylation in glioblastoma are unknown. We used CRISPR/Cas9 to knockout PREX1, a PI 3-kinase pathway-responsive Rac guanine nucleotide exchange factor, in patient-derived glioblastoma cells. Knockout cells had reduced Lgl1 phosphorylation, which was reversed by re-expressing PREX1. They also had reduced motility and an altered phenotype suggestive of partial neuronal differentiation; consistent with this, RNA-seq analyses identified sets of PREX1-regulated genes associated with cell motility and neuronal differentiation. PREX1 knockout in glioblastoma cells from a second patient did not affect Lgl1 phosphorylation. This was due to overexpression of a short isoform of the Rac guanine nucleotide exchange factor TIAM1; knockdown of TIAM1 in these PREX1 knockout cells reduced Lgl1 phosphorylation. These data show that PREX1 links aberrant PI 3-kinase signaling to Lgl1 phosphorylation in glioblastoma, but that TIAM1 is also to fill this role in a subset of patients. This redundancy between PREX1 and TIAM1 is only partial, as motility was impaired in PREX1 knockout cells from both patients.
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Affiliation(s)
- Sylvie J Lavictoire
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Danny Jomaa
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada; School of Medicine, Faculty of Health Sciences, Queen's University, Kingston, Ontario, Canada
| | - Alexander Gont
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Karen Jardine
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - David P Cook
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Ian A J Lorimer
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada; Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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8
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Liang Q, Chang Y, Liu J, Yu Y, Qiu W, Li J, Yang X, Sun G. P-Rex1 Cooperates With TGFβR2 to Drive Lung Fibroblast Migration in Pulmonary Fibrosis. Front Pharmacol 2021; 12:678733. [PMID: 34349645 PMCID: PMC8326510 DOI: 10.3389/fphar.2021.678733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
Pulmonary fibrosis is a kind of interstitial lung disease with progressive pulmonary scar formation, leading to irreversible loss of lung functions. The TGF-β1/Smad signaling pathway plays a key role in fibrogenic processes. It is associated with the increased synthesis of extracellular matrix, enhanced proliferation of fibroblasts, and transformation of alveolar epithelial cells into interstitial cells. We investigated P-Rex1, a PIP3-Gβγ-dependent guanine nucleotide exchange factor (GEF) for Rac, for its potential role in TGF-β1-induced pulmonary fibrosis. A high expression level of P-Rex1 was identified in the lung tissue of patients with pulmonary fibrosis than that from healthy donors. Using the P-Rex1 knockdown and overexpression system, we established a novel player of P-Rex1 in mouse lung fibroblast migration. P-Rex1 contributed to fibrogenic processes in lung fibroblasts by targeting the TGF-β type Ⅱ receptor (TGFβR2). The RNA-seq analysis for expression profiling confirmed the modulation of P-Rex1 in cell migration and the involvement of P-Rex1 in TGF-β1 signaling. These results identified P-Rex1 as a signaling molecule involved in TGF-β1-induced pulmonary fibrosis, suggesting that P-Rex1 may be a potential target for pulmonary fibrosis treatment.
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Affiliation(s)
- Qing Liang
- Department of Pharmacy, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Yanhua Chang
- Department of Pathology, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi, China
| | - Jing Liu
- Department of Pharmacy, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Yan Yu
- Department of Pharmacy, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Wancheng Qiu
- Department of Pharmacy, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Jiajia Li
- Department of Pharmacy, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Xu Yang
- Department of Pharmacy, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Guangchun Sun
- Department of Pharmacy, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
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9
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D'Andrea L, Lucato CM, Marquez EA, Chang YG, Civciristov S, Mastos C, Lupton CJ, Huang C, Elmlund H, Schittenhelm RB, Mitchell CA, Whisstock JC, Halls ML, Ellisdon AM. Structural analysis of the PTEN:P-Rex2 signaling complex reveals how cancer-associated mutations coordinate to hyperactivate Rac1. Sci Signal 2021; 14:14/681/eabc4078. [PMID: 33947796 DOI: 10.1126/scisignal.abc4078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The dual-specificity phosphatase PTEN functions as a tumor suppressor by hydrolyzing PI(3,4,5)P3 to PI(4,5)P2 to inhibit PI3K-AKT signaling and cellular proliferation. P-Rex2 is a guanine nucleotide exchange factor for Rho GTPases and can be activated by Gβγ subunits downstream of G protein-coupled receptor signaling and by PI(3,4,5)P3 downstream of receptor tyrosine kinases. The PTEN:P-Rex2 complex is a commonly mutated signaling node in metastatic cancer. Assembly of the PTEN:P-Rex2 complex inhibits the activity of both proteins, and its dysregulation can drive PI3K-AKT signaling and cellular proliferation. Here, using cross-linking mass spectrometry and functional studies, we gained mechanistic insights into PTEN:P-Rex2 complex assembly and coinhibition. We found that PTEN was anchored to P-Rex2 by interactions between the PDZ-interacting motif in the PTEN C-terminal tail and the second PDZ domain of P-Rex2. This interaction bridged PTEN across the P-Rex2 surface, preventing PI(3,4,5)P3 hydrolysis. Conversely, PTEN both allosterically promoted an autoinhibited conformation of P-Rex2 and blocked its binding to Gβγ. In addition, we observed that the PTEN-deactivating mutations and P-Rex2 truncations combined to drive Rac1 activation to a greater extent than did either single variant alone. These insights enabled us to propose a class of gain-of-function, cancer-associated mutations within the PTEN:P-Rex2 interface that uncouple PTEN from the inhibition of Rac1 signaling.
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Affiliation(s)
- Laura D'Andrea
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Christina M Lucato
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Elsa A Marquez
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Yong-Gang Chang
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Srgjan Civciristov
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052 Victoria, Australia
| | - Chantel Mastos
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052 Victoria, Australia
| | - Christopher J Lupton
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Cheng Huang
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.,Monash Proteomics & Metabolomics Facility, Monash University, Clayton, 3800 Victoria, Australia
| | - Hans Elmlund
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - Ralf B Schittenhelm
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.,Monash Proteomics & Metabolomics Facility, Monash University, Clayton, 3800 Victoria, Australia
| | - Christina A Mitchell
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia
| | - James C Whisstock
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, 3800 Victoria, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052 Victoria, Australia.
| | - Andrew M Ellisdon
- Biomedicine Discovery Institute, Monash University, Clayton, 3800 Victoria, Australia.
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10
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Machin PA, Tsonou E, Hornigold DC, Welch HCE. Rho Family GTPases and Rho GEFs in Glucose Homeostasis. Cells 2021; 10:cells10040915. [PMID: 33923452 PMCID: PMC8074089 DOI: 10.3390/cells10040915] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/11/2021] [Accepted: 04/13/2021] [Indexed: 12/17/2022] Open
Abstract
Dysregulation of glucose homeostasis leading to metabolic syndrome and type 2 diabetes is the cause of an increasing world health crisis. New intriguing roles have emerged for Rho family GTPases and their Rho guanine nucleotide exchange factor (GEF) activators in the regulation of glucose homeostasis. This review summates the current knowledge, focusing in particular on the roles of Rho GEFs in the processes of glucose-stimulated insulin secretion by pancreatic β cells and insulin-stimulated glucose uptake into skeletal muscle and adipose tissues. We discuss the ten Rho GEFs that are known so far to regulate glucose homeostasis, nine of which are in mammals, and one is in yeast. Among the mammalian Rho GEFs, P-Rex1, Vav2, Vav3, Tiam1, Kalirin and Plekhg4 were shown to mediate the insulin-stimulated translocation of the glucose transporter GLUT4 to the plasma membrane and/or insulin-stimulated glucose uptake in skeletal muscle or adipose tissue. The Rho GEFs P-Rex1, Vav2, Tiam1 and β-PIX were found to control the glucose-stimulated release of insulin by pancreatic β cells. In vivo studies demonstrated the involvement of the Rho GEFs P-Rex2, Vav2, Vav3 and PDZ-RhoGEF in glucose tolerance and/or insulin sensitivity, with deletion of these GEFs either contributing to the development of metabolic syndrome or protecting from it. This research is in its infancy. Considering that over 80 Rho GEFs exist, it is likely that future research will identify more roles for Rho GEFs in glucose homeostasis.
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Affiliation(s)
- Polly A. Machin
- Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; (P.A.M.); (E.T.)
| | - Elpida Tsonou
- Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; (P.A.M.); (E.T.)
- Bioscience Metabolism, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge CB22 3AT, UK;
| | - David C. Hornigold
- Bioscience Metabolism, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Cambridge CB22 3AT, UK;
| | - Heidi C. E. Welch
- Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK; (P.A.M.); (E.T.)
- Correspondence: ; Tel.: +44-(0)1223-496-596
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11
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Abstract
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Rac1 is a small GTPase
that plays key roles in actin reorganization,
cell motility, and cell survival/growth as well as in various cancer
types and neurodegenerative diseases. Similar to other Ras superfamily
GTPases, Rac1 switches between active GTP-bound and inactive GDP-bound
states. Switch I and II regions open and close during GDP/GTP exchange.
P29S and A159V (paralogous to K-RasA146) mutations are
the two most common somatic mutations of Rac1. Rac1P29S is a known hotspot for melanoma, whereas Rac1A159V most
commonly occurs in head and neck cancer. To investigate how these
substitutions induce the Rac1 dynamics, we used atomistic molecular
dynamics simulations on the wild-type Rac1 and two mutant systems
(P29S and A159V) in the GTP bound state, and on the wild-type Rac1
and P29S mutated system in the GDP bound state. Here, we show that
P29S and A159V mutations activate Rac1 with different mechanisms.
In Rac1P29S-GTP, the substitution increases the flexibility
of Switch I based on RMSF and dihedral angle calculations and leads
to an open conformation. We propose that the open Switch I conformation
is one of the underlying reasons for rapid GDP/GTP exchange of Rac1P29S. On the other hand, in Rac1A159V-GTP, some
of the contacts of the guanosine ring of GTP with Rac1 are temporarily
lost, enabling the guanosine ring to move toward Switch I and subsequently
close the switch. Rac1A159V-GTP adopts a Ras state 2 like
conformation, where both switch regions are in closed conformation
and Thr35 forms a hydrogen bond with the nucleotide.
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Affiliation(s)
- Simge Senyuz
- Computational Science and Engineering, Koc University, Rumelifeneri Yolu, 34450 Sariyer, Istanbul, Turkey
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland 21702, United States.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ozlem Keskin
- Chemical and Biological Engineering, Koc University, Rumelifeneri Yolu, 34450 Sariyer, Istanbul, Turkey
| | - Attila Gursoy
- Computer Engineering, Koc University, Rumelifeneri Yolu, 34450 Sariyer, Istanbul, Turkey
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12
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Castillo-Kauil A, García-Jiménez I, Cervantes-Villagrana RD, Adame-García SR, Beltrán-Navarro YM, Gutkind JS, Reyes-Cruz G, Vázquez-Prado J. Gα s directly drives PDZ-RhoGEF signaling to Cdc42. J Biol Chem 2020; 295:16920-16928. [PMID: 33023908 PMCID: PMC7863908 DOI: 10.1074/jbc.ac120.015204] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/24/2020] [Indexed: 12/16/2022] Open
Abstract
Gα proteins promote dynamic adjustments of cell shape directed by actin-cytoskeleton reorganization via their respective RhoGEF effectors. For example, Gα13 binding to the RGS-homology (RH) domains of several RH-RhoGEFs allosterically activates these proteins, causing them to expose their catalytic Dbl-homology (DH)/pleckstrin-homology (PH) regions, which triggers downstream signals. However, whether additional Gα proteins might directly regulate the RH-RhoGEFs was not known. To explore this question, we first examined the morphological effects of expressing shortened RH-RhoGEF DH/PH constructs of p115RhoGEF/ARHGEF1, PDZ-RhoGEF (PRG)/ARHGEF11, and LARG/ARHGEF12. As expected, the three constructs promoted cell contraction and activated RhoA, known to be downstream of Gα13 Intriguingly, PRG DH/PH also induced filopodia-like cell protrusions and activated Cdc42. This pathway was stimulated by constitutively active Gαs (GαsQ227L), which enabled endogenous PRG to gain affinity for Cdc42. A chemogenetic approach revealed that signaling by Gs-coupled receptors, but not by those coupled to Gi or Gq, enabled PRG to bind Cdc42. This receptor-dependent effect, as well as CREB phosphorylation, was blocked by a construct derived from the PRG:Gαs-binding region, PRG-linker. Active Gαs interacted with isolated PRG DH and PH domains and their linker. In addition, this construct interfered with GαsQ227L's ability to guide PRG's interaction with Cdc42. Endogenous Gs-coupled prostaglandin receptors stimulated PRG binding to membrane fractions and activated signaling to PKA, and this canonical endogenous pathway was attenuated by PRG-linker. Altogether, our results demonstrate that active Gαs can recognize PRG as a novel effector directing its DH/PH catalytic module to gain affinity for Cdc42.
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Affiliation(s)
- Alejandro Castillo-Kauil
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Irving García-Jiménez
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Sendi Rafael Adame-García
- Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Yarely Mabell Beltrán-Navarro
- Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - J Silvio Gutkind
- Moores Cancer Center and Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
| | - Guadalupe Reyes-Cruz
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - José Vázquez-Prado
- Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.
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13
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Arrington ME, Temple B, Schaefer A, Campbell SL. The molecular basis for immune dysregulation by the hyperactivated E62K mutant of the GTPase RAC2. J Biol Chem 2020; 295:12130-12142. [PMID: 32636302 PMCID: PMC7443499 DOI: 10.1074/jbc.ra120.012915] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 07/02/2020] [Indexed: 12/20/2022] Open
Abstract
The RAS-related C3 botulinum toxin substrate 2 (RAC2) is a member of the RHO subclass of RAS superfamily GTPases required for proper immune function. An activating mutation in a key switch II region of RAC2 (RAC2E62K) involved in recognizing modulatory factors and effectors has been identified in patients with common variable immune deficiency. To better understand how the mutation dysregulates RAC2 function, we evaluated the structure and stability, guanine nucleotide exchange factor (GEF) and GTPase-activating protein (GAP) activity, and effector binding of RAC2E62K Our findings indicate the E62K mutation does not alter RAC2 structure or stability. However, it does alter GEF specificity, as RAC2E62K is activated by the DOCK GEF, DOCK2, but not by the Dbl homology GEF, TIAM1, both of which activate the parent protein. Our previous data further showed that the E62K mutation impairs GAP activity for RAC2E62K As this disease mutation is also found in RAS GTPases, we assessed GAP-stimulated GTP hydrolysis for KRAS and observed a similar impairment, suggesting that the mutation plays a conserved role in GAP activation. We also investigated whether the E62K mutation alters effector binding, as activated RAC2 binds effectors to transmit signaling through effector pathways. We find that RAC2E62K retains binding to an NADPH oxidase (NOX2) subunit, p67phox, and to the RAC-binding domain of p21-activated kinase, consistent with our earlier findings. Taken together, our findings indicate that the RAC2E62K mutation promotes immune dysfunction by promoting RAC2 hyperactivation, altering GEF specificity, and impairing GAP function yet retaining key effector interactions.
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Affiliation(s)
- Megan E Arrington
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Brenda Temple
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA; R. L. Juliano Structural Bioinformatics Core Facility, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Antje Schaefer
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA.
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14
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Chamberlin A, Huether R, Machado AZ, Groden M, Liu HM, Upadhyay K, O V, Gomes NL, Lerario AM, Nishi MY, Costa EMF, Mendonca B, Domenice S, Velasco J, Loke J, Ostrer H. Mutations in MAP3K1 that cause 46,XY disorders of sex development disrupt distinct structural domains in the protein. Hum Mol Genet 2020; 28:1620-1628. [PMID: 30608580 DOI: 10.1093/hmg/ddz002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/19/2018] [Accepted: 12/31/2018] [Indexed: 02/07/2023] Open
Abstract
Missense mutations in the gene, MAP3K1, are a common cause of 46,XY gonadal dysgenesis, accounting for 15-20% of cases [Ostrer, 2014, Disorders of sex development (DSDs): an update. J. Clin. Endocrinol. Metab., 99, 1503-1509]. Functional studies demonstrated that all of these mutations cause a protein gain-of-function that alters co-factor binding and increases phosphorylation of the downstream MAP kinase pathway targets, MAPK11, MAP3K and MAPK1. This dysregulation of the MAP kinase pathway results in increased CTNNB1, increased expression of WNT4 and FOXL2 and decreased expression of SRY and SOX9. Unique and recurrent pathogenic mutations cluster in three semi-contiguous domains outside the kinase region of the protein, a newly identified N-terminal domain that shares homology with the Guanine Exchange Factor (residues Met164 to Glu231), a Plant HomeoDomain (residues Met442 to Trp495) and an ARMadillo repeat domain (residues Met566 to Glu862). Despite the presence of the mutation clusters and clinical data, there exists a dearth of mechanistic insights behind the development imbalance. In this paper, we use structural modeling and functional data of these mutations to understand alterations of the MAP3K1 protein and the effects on protein folding, binding and downstream target phosphorylation. We show that these mutations have differential effects on protein binding depending on the domains in which they occur. These mutations increase the binding of the RHOA, MAP3K4 and FRAT1 proteins and generally decrease the binding of RAC1. Thus, pathologies in MAP3K1 disrupt the balance between the pro-kinase activities of the RHOA and MAP3K4 binding partners and the inhibitory activity of RAC1.
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Affiliation(s)
| | | | - Aline Z Machado
- Division of Endocrinology, Hormone and Molecular Genetics Laboratory (LIM), Hospital das Clinicas, University of Sao Paulo Medical School, Avenida Dr. Eneas de C Aguiar, andar Bloco, São Paulo, SP, Brazil
| | - Michael Groden
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | - Kinnari Upadhyay
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Vivian O
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Nathalia L Gomes
- Division of Endocrinology, Hormone and Molecular Genetics Laboratory (LIM), Hospital das Clinicas, University of Sao Paulo Medical School, Avenida Dr. Eneas de C Aguiar, andar Bloco, São Paulo, SP, Brazil
| | - Antonio M Lerario
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Mirian Y Nishi
- Division of Endocrinology, Hormone and Molecular Genetics Laboratory (LIM), Hospital das Clinicas, University of Sao Paulo Medical School, Avenida Dr. Eneas de C Aguiar, andar Bloco, São Paulo, SP, Brazil
| | - Elaine M F Costa
- Division of Endocrinology, Hormone and Molecular Genetics Laboratory (LIM), Hospital das Clinicas, University of Sao Paulo Medical School, Avenida Dr. Eneas de C Aguiar, andar Bloco, São Paulo, SP, Brazil
| | - Berenice Mendonca
- Division of Endocrinology, Hormone and Molecular Genetics Laboratory (LIM), Hospital das Clinicas, University of Sao Paulo Medical School, Avenida Dr. Eneas de C Aguiar, andar Bloco, São Paulo, SP, Brazil
| | - Sorahia Domenice
- Division of Endocrinology, Hormone and Molecular Genetics Laboratory (LIM), Hospital das Clinicas, University of Sao Paulo Medical School, Avenida Dr. Eneas de C Aguiar, andar Bloco, São Paulo, SP, Brazil
| | | | - Johnny Loke
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Harry Ostrer
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
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15
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Ye RD. The Rho guanine nucleotide exchange factor P-Rex1 as a potential drug target for cancer metastasis and inflammatory diseases. Pharmacol Res 2020; 153:104676. [PMID: 32006571 DOI: 10.1016/j.phrs.2020.104676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/12/2020] [Accepted: 01/27/2020] [Indexed: 12/13/2022]
Abstract
Phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger 1 (P-Rex1) is a guanine nucleotide exchange factor (GEF) for Rac small GTPases and the Rac-related GTPase RhoG. P-Rex1 plays an important role in cell migration and relays intracellular signals generated through activation of G protein-coupled receptors and receptor tyrosine kinases. Studies of mouse models have found that P-Rex1 expression and activation is associated with tumor cell migration, brain development and pathological changes such as lung edema. Since its initial discovery, P-Rex1 has been known for its large size and multiple activation mechanisms that involve not only PIP3 but also the βγ subunits of heterotrimeric G proteins and a regulatory subunit of cyclic AMP-dependent kinase, PKA RIα. At the core of the GEF activity is the tandem Dbl homology domain and the pleckstrin homology domain (DH/PH domains) that are masked until activation signals unwind the P-Rex1 structure. Understanding the activation mechanisms will help designing therapeutics that target P-Rex1 for cancer and other diseases.
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16
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Shao Q, Chen ZM. Feedback regulation between phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1 and transforming growth factor β1 and prognostic value in gastric cancer. World J Gastroenterol 2020; 26:21-34. [PMID: 31933512 PMCID: PMC6952301 DOI: 10.3748/wjg.v26.i1.21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/15/2019] [Accepted: 12/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 1 (PREX1) was reported to be overexpressed in some cancers and involved in cancer development, but its expression and significance in gastric cancer remain unclear.
AIM To evaluate the expression of PREX1 in gastric cancer and its significance in the development of gastric cancer, especially to evaluate the potential mechanism of PREX1 in gastric cancer.
METHODS Bioinformatic analysis was performed in order to examine the expression of PREX1 in gastric cancer. The relationship between the survival rate of gastric cancer patients and PREX1 expression was assessed by Kaplan Meier portal. The Gene Set Enrichment Analysis and the correlation between PREX1 and transforming growth factor (TGF) β1 pathway-related mediators were evaluated by cBioPortal for Cancer Genomics. Western blotting and reverse transcriptase polymerase chain reaction assay were used to test the role of TGFβ1 on the expression of PREX1. Western blotting and dual-luciferase reporter system was used to evaluate the effect of PREX1 on the activation of TGFβ1 pathway. Wound healing and Transwell assay were used to assess the effect of PREX1 on the metastasis activity of gastric cancer cells.
RESULTS PREX1 was overexpressed in the gastric tumors, and the expression levels were positively associated with the development of gastric cancer. Also, the high expression of PREX1 revealed poor prognosis, especially for those advanced and specific intestinal gastric cancer patients. PREX1 was closely involved in the positive regulation of cell adhesion and positively correlated with TGFβ1-related mediators. Furthermore, TGFβ1 could induce the expression of PREX1 at both the protein and mRNA level. Also, PREX1 could activate the TGFβ1 pathway. The induced PREX1 could increase the migration and invasion activity of gastric cancer cells.
CONCLUSION PREX1 is overexpressed in gastric cancer, and the high level of PREX1 predicts poor prognosis. PREX1 is closely associated with TGFβ signaling and promotes the metastasis of gastric cancer cells.
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Affiliation(s)
- Qi Shao
- Department of Chemotherapy/Radiotherapy, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China
| | - Zhi-Ming Chen
- Department of Chemotherapy/Radiotherapy, Affiliated Hospital of Nantong University, Nantong 226001, Jiangsu Province, China
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17
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Cash JN, Urata S, Li S, Ravala SK, Avramova LV, Shost MD, Gutkind JS, Tesmer JJG, Cianfrocco MA. Cryo-electron microscopy structure and analysis of the P-Rex1-Gβγ signaling scaffold. Sci Adv 2019; 5:eaax8855. [PMID: 31663027 PMCID: PMC6795519 DOI: 10.1126/sciadv.aax8855] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 09/22/2019] [Indexed: 05/29/2023]
Abstract
PIP3-dependent Rac exchanger 1 (P-Rex1) is activated downstream of G protein-coupled receptors to promote neutrophil migration and metastasis. The structure of more than half of the enzyme and its regulatory G protein binding site are unknown. Our 3.2 Å cryo-EM structure of the P-Rex1-Gβγ complex reveals that the carboxyl-terminal half of P-Rex1 adopts a complex fold most similar to those of Legionella phosphoinositide phosphatases. Although catalytically inert, the domain coalesces with a DEP domain and two PDZ domains to form an extensive docking site for Gβγ. Hydrogen-deuterium exchange mass spectrometry suggests that Gβγ binding induces allosteric changes in P-Rex1, but functional assays indicate that membrane localization is also required for full activation. Thus, a multidomain assembly is key to the regulation of P-Rex1 by Gβγ and the formation of a membrane-localized scaffold optimized for recruitment of other signaling proteins such as PKA and PTEN.
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Affiliation(s)
- Jennifer N. Cash
- Department of Biological Chemistry & Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Sarah Urata
- Department of Medicine, University of California, San Diego, San Diego, CA, USA
| | - Sheng Li
- Department of Medicine, University of California, San Diego, San Diego, CA, USA
| | - Sandeep K. Ravala
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Larisa V. Avramova
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Michael D. Shost
- Department of Biological Chemistry & Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - J. Silvio Gutkind
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, San Diego, CA, USA
| | - John J. G. Tesmer
- Departments of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Michael A. Cianfrocco
- Department of Biological Chemistry & Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
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18
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Xicola RM, Manojlovic Z, Augustus GJ, Kupfer SS, Emmadi R, Alagiozian-Angelova V, Triche T, Salhia B, Carpten J, Llor X, Ellis NA. Lack of APC somatic mutation is associated with early-onset colorectal cancer in African Americans. Carcinogenesis 2019; 39:1331-1341. [PMID: 30239619 DOI: 10.1093/carcin/bgy122] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 09/11/2018] [Indexed: 02/06/2023] Open
Abstract
African Americans (AAs) have higher incidence and mortality rates of colorectal cancer (CRC) compared with other US populations. They present with more right-sided, microsatellite stable disease and are diagnosed at earlier ages compared with non-Hispanic Whites (NHWs). To gain insight into these trends, we conducted exome sequencing (n = 45), copy number (n = 33) and methylation analysis (n = 11) of microsatellite stable AA CRCs. Results were compared with data from The Cancer Genome Atlas (TCGA). Two of the 45 tumors contained POLE mutations. In the remaining 43 tumors, only 27 (63%) contained loss-of-function mutations in APC compared with 80% of TCGA NHW CRCs. APC-mutation-negative CRCs were associated with an earlier onset of CRC (P = 0.01). They were also associated with lower overall mutation burden, fewer copy number variants and a DNA methylation signature that was distinct from the CpG island methylator phenotype characterized in microsatellite unstable disease. Three of the APC-mutation-negative CRCs had loss-of-function mutations in BCL9L. Mutations in driver genes identified by TCGA exome analysis were less frequent in AA CRC cases than TCGA NHWs. Genes that regulate the WNT signaling pathway, including SOX9, GATA6, TET1, GLIS1 and FAT1, were differentially hypermethylated in APC-mutation-negative CRCs, suggesting a novel mechanism for cancer development in these tumors. In summary, we have identified a subtype of CRC that is associated with younger age of diagnosis, lack of APC mutation, microsatellite and chromosome stability, lower mutation burden and distinctive methylation changes.
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Affiliation(s)
- Rosa M Xicola
- Department of Internal Medicine and Yale Cancer Center, Yale University, New Haven, CT, USA
| | - Zarko Manojlovic
- Translational Genomics Research Institute, Division of Integrated Cancer Genomics, Phoenix, AZ, USA.,Department of Translational Genomics, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Gaius J Augustus
- Cancer Biology Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA
| | - Sonia S Kupfer
- University of Chicago Medicine, Section of Gastroenterology, Hepatology and Nutrition, Chicago, IL, USA
| | - Rajyasree Emmadi
- Department of Pathology, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Tim Triche
- Department of Translational Genomics, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA.,Center for Epigenetics, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Bodour Salhia
- Department of Translational Genomics, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - John Carpten
- Translational Genomics Research Institute, Division of Integrated Cancer Genomics, Phoenix, AZ, USA.,Department of Translational Genomics, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Xavier Llor
- Department of Internal Medicine and Yale Cancer Center, Yale University, New Haven, CT, USA
| | - Nathan A Ellis
- Department of Cellular and Molecular Medicine and University of Arizona Cancer Center, University of Arizona., Tucson, AZ, USA
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19
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Ijuin T. Phosphoinositide phosphatases in cancer cell dynamics-Beyond PI3K and PTEN. Semin Cancer Biol 2019; 59:50-65. [PMID: 30922959 DOI: 10.1016/j.semcancer.2019.03.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 12/16/2022]
Abstract
Phosphoinositides are a group of lipids that regulate intracellular signaling and subcellular biological events. The signaling by phosphatidylinositol-3,4,5-trisphosphate and Akt mediates the action of growth factors that are essential for cell proliferation, gene transcription, cell migration, and polarity. The hyperactivation of this signaling has been identified in different cancer cells; and, it has been implicated in oncogenic transformation and cancer cell malignancy. Recent studies have argued the role of phosphoinositides in cancer cell dynamics, including actin cytoskeletal rearrangement at the plasma membrane and the organization of intracellular compartments. The focus of this review is to summarize the impact of the activities of phosphoinositide phosphatases on intracellular signaling related to cancer cell dynamics and to discuss how the abnormalities in the activities of the enzymes alter the levels of phosphoinositides in cancer cells.
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Affiliation(s)
- Takeshi Ijuin
- Division of Biochemistry, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki, Chu-o, Kobe 650-0017, Japan.
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20
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Adame-García SR, Cervantes-Villagrana RD, Orduña-Castillo LB, Del Rio JC, Gutkind JS, Reyes-Cruz G, Taylor SS, Vázquez-Prado J. cAMP-dependent activation of the Rac guanine exchange factor P-REX1 by type I protein kinase A (PKA) regulatory subunits. J Biol Chem 2019; 294:2232-2246. [PMID: 30530493 PMCID: PMC6378977 DOI: 10.1074/jbc.ra118.006691] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 11/29/2018] [Indexed: 12/22/2022] Open
Abstract
Regulatory subunits of protein kinase A (PKA) inhibit its kinase subunits. Intriguingly, their potential as cAMP-dependent signal transducers remains uncharacterized. We recently reported that type I PKA regulatory subunits (RIα) interact with phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchange factor 1 (P-REX1), a chemotactic Rac guanine exchange factor (RacGEF). Because P-REX1 is known to be phosphorylated and inhibited by PKA, its interaction with RIα suggests that PKA regulatory and catalytic subunits may fine-tune P-REX1 activity or those of its target pools. Here, we tested whether RIα acts as a cAMP-dependent factor promoting P-REX1-mediated Rac activation and cell migration. We observed that Gs-coupled EP2 receptors indeed promote endothelial cell migration via RIα-activated P-REX1. Expression of the P-REX1-PDZ1 domain prevented RIα/P-REX1 interaction, P-REX1 activation, and EP2-dependent cell migration, and P-REX1 silencing abrogated RIα-dependent Rac activation. RIα-specific cAMP analogs activated P-REX1, but lost this activity in RIα-knockdown cells, and cAMP pulldown assays revealed that P-REX1 preferentially interacts with free RIα. Moreover, purified RIα directly activated P-REX1 in vitro We also found that the RIα CNB-B domain is critical for the interaction with P-REX1, which was increased in RIα mutants, such as the acrodysostosis-associated mutant, that activate P-REX1 at basal cAMP levels. RIα and Cα PKA subunits targeted distinct P-REX1 molecules, indicated by an absence of phosphorylation in the active fraction of P-REX1. This was in contrast to the inactive fraction in which phosphorylated P-REX1 was present, suggesting co-existence of dual stimulatory and inhibitory effects. We conclude that PKA's regulatory subunits are cAMP-dependent signal transducers.
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Affiliation(s)
| | | | | | | | | | | | - Susan S Taylor
- the Departments of Pharmacology
- Chemistry and
- Biochemistry, University of California San Diego, La Jolla, California 92093
| | - José Vázquez-Prado
- Pharmacology, Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN), 07360 Mexico City, Mexico and
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21
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Cash JN, Sharma PV, Tesmer JJ. Structural and biochemical characterization of the pleckstrin homology domain of the RhoGEF P-Rex2 and its regulation by PIP 3. J Struct Biol X 2018; 1:100001. [PMID: 34958187 PMCID: PMC7337056 DOI: 10.1016/j.yjsbx.2018.100001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/27/2018] [Accepted: 12/04/2018] [Indexed: 01/07/2023] Open
Abstract
P-Rex family Rho guanine-nucleotide exchange factors are important regulators of cell motility through their activation of a subset of small GTPases. Both P-Rex1 and P-Rex2 have also been implicated in the progression of certain cancers, including breast cancer and melanoma. Although these molecules display a high level of homology, differences exist in tissue distribution, physiological function, and regulation at the molecular level. Here, we sought to compare the P-Rex2 pleckstrin homology (PH) domain structure and ability to interact with PIP3 with those of P-Rex1. The 1.9 Å crystal structure of the P-Rex2 PH domain reveals conformational differences in the loop regions, yet biochemical studies indicate that the interaction of the P-Rex2 PH domain with PIP3 is very similar to that of P-Rex1. Binding of the PH domain to PIP3 is critical for P-Rex2 activity but not membrane localization, as previously demonstrated for P-Rex1. These studies serve as a starting point in the identification of P-Rex structural features that are divergent between isoforms and could be exploited for the design of P-Rex selective compounds.
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Key Words
- DEP, dishevelled, Egl-10, and pleckstrin
- DH, Dbl homology
- DSF, differential scanning fluorimetry
- DTT, dithiothreitol
- EDTA, ethylenediaminetetraacetic
- Gβγ, G protein β and γ subunits
- IP4P, inositol polyphosphate 4-phosphatase
- Ins(1,3,4,5)P4, inositol-1,3,4,5-tetrakisphosphate
- MBP, maltose binding protein
- P-Rex
- P-Rex, phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger
- PDZ, post-synaptic density protein, Drosophila disc large tumor suppressor, and zonula occludens-1 protein
- PH, pleckstrin homology
- PIP3, phosphatidylinositol 3,4,5-trisphosphate
- PMSF, phenylmethylsulfonyl fluoride
- PTEN, phosphatase and tensin homolog
- Phosphatidylinositol 3,4,5-trisphosphate
- Pleckstrin homology domain
- Rho guanine nucleotide exchange factor
- RhoGEF, Rho guanine-nucleotide exchange factor
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Affiliation(s)
- Jennifer N. Cash
- Department of Pharmacology, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA,Department of Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Prateek V. Sharma
- Department of Pharmacology, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA,Department of Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - John J.G. Tesmer
- Department of Biological Sciences and of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47904, USA,Corresponding author.
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22
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Nørgaard S, Deng S, Cao W, Pocock R. Distinct CED-10/Rac1 domains confer context-specific functions in development. PLoS Genet 2018; 14:e1007670. [PMID: 30265669 PMCID: PMC6179291 DOI: 10.1371/journal.pgen.1007670] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/10/2018] [Accepted: 08/30/2018] [Indexed: 11/18/2022] Open
Abstract
Rac GTPases act as master switches to coordinate multiple interweaved signaling pathways. A major function for Rac GTPases is to control neurite development by influencing downstream effector molecules and pathways. In Caenorhabditis elegans, the Rac proteins CED-10, RAC-2 and MIG-2 act in parallel to control axon outgrowth and guidance. Here, we have identified a single glycine residue in the CED-10/Rac1 Switch 1 region that confers a non-redundant function in axon outgrowth but not guidance. Mutation of this glycine to glutamic acid (G30E) reduces GTP binding and inhibits axon outgrowth but does not affect other canonical CED-10 functions. This demonstrates previously unappreciated domain-specific functions within the CED-10 protein. Further, we reveal that when CED-10 function is diminished, the adaptor protein NAB-1 (Neurabin) and its interacting partner SYD-1 (Rho-GAP-like protein) can act as inhibitors of axon outgrowth. Together, we reveal that specific domains and residues within Rac GTPases can confer context-dependent functions during animal development. Brain development requires that neurite outgrowth and guidance are precisely regulated. Previous studies have shown that molecular switch proteins called Rac GTPases perform redundant functions in controlling neurite development. Using a pair of bilateral neurons in the nematode Caenorhabditis elegans to model neurite development, we found that a single amino acid in a conserved domain of the Rac GTPase CED-10 is crucial for controlling neurite outgrowth in a partially non-redundant manner. Further, we revealed that lesions in discrete domains in the CED-10 protein lead to distinct developmental defects. Therefore, our in vivo study proposes that regulation of distinct signalling pathways through Rac GTPase protein domains can drive different developmental outcomes.
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Affiliation(s)
- Steffen Nørgaard
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
- Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Shuer Deng
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Wei Cao
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
- Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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23
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Rosmaninho P, Mükusch S, Piscopo V, Teixeira V, Raposo AA, Warta R, Bennewitz R, Tang Y, Herold-Mende C, Stifani S, Momma S, Castro DS. Zeb1 potentiates genome-wide gene transcription with Lef1 to promote glioblastoma cell invasion. EMBO J 2018; 37:e97115. [PMID: 29903919 PMCID: PMC6068449 DOI: 10.15252/embj.201797115] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 04/27/2018] [Accepted: 05/07/2018] [Indexed: 12/30/2022] Open
Abstract
Glioblastoma is the most common and aggressive brain tumor, with a subpopulation of stem-like cells thought to mediate its recurring behavior and therapeutic resistance. The epithelial-mesenchymal transition (EMT) inducing factor Zeb1 was linked to tumor initiation, invasion, and resistance to therapy in glioblastoma, but how Zeb1 functions at molecular level and what genes it regulates remain poorly understood. Contrary to the common view that EMT factors act as transcriptional repressors, here we show that genome-wide binding of Zeb1 associates with both activation and repression of gene expression in glioblastoma stem-like cells. Transcriptional repression requires direct DNA binding of Zeb1, while indirect recruitment to regulatory regions by the Wnt pathway effector Lef1 results in gene activation, independently of Wnt signaling. Amongst glioblastoma genes activated by Zeb1 are predicted mediators of tumor cell migration and invasion, including the guanine nucleotide exchange factor Prex1, whose elevated expression is predictive of shorter glioblastoma patient survival. Prex1 promotes invasiveness of glioblastoma cells in vivo highlighting the importance of Zeb1/Lef1 gene regulatory mechanisms in gliomagenesis.
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Affiliation(s)
- Pedro Rosmaninho
- Molecular Neurobiology Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Susanne Mükusch
- Institute of Neurology (Edinger Institute), Frankfurt University Medical School, Frankfurt, Germany
- German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Valerio Piscopo
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Vera Teixeira
- Molecular Neurobiology Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Alexandre Asf Raposo
- Molecular Neurobiology Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Rolf Warta
- Division of Experimental Neurosurgery, Department of Neurosurgery, University Hospital of Heidelberg, Heidelberg, Germany
| | - Romina Bennewitz
- Institute of Neurology (Edinger Institute), Frankfurt University Medical School, Frankfurt, Germany
- German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Yeman Tang
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Christel Herold-Mende
- Division of Experimental Neurosurgery, Department of Neurosurgery, University Hospital of Heidelberg, Heidelberg, Germany
| | - Stefano Stifani
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Stefan Momma
- Institute of Neurology (Edinger Institute), Frankfurt University Medical School, Frankfurt, Germany
- German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Diogo S Castro
- Molecular Neurobiology Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
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24
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López Tobón A, Suresh M, Jin J, Vitriolo A, Pietralla T, Tedford K, Bossenz M, Mahnken K, Kiefer F, Testa G, Fischer KD, Püschel AW. The guanine nucleotide exchange factor Arhgef7/βPix promotes axon formation upstream of TC10. Sci Rep 2018; 8:8811. [PMID: 29891904 PMCID: PMC5995858 DOI: 10.1038/s41598-018-27081-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/29/2018] [Indexed: 11/10/2022] Open
Abstract
The characteristic six layers of the mammalian neocortex develop sequentially as neurons are generated by neural progenitors and subsequently migrate past older neurons to their final position in the cortical plate. One of the earliest steps of neuronal differentiation is the formation of an axon. Small GTPases play essential roles during this process by regulating cytoskeletal dynamics and intracellular trafficking. While the function of GTPases has been studied extensively in cultured neurons and in vivo much less is known about their upstream regulators. Here we show that Arhgef7 (also called βPix or Cool1) is essential for axon formation during cortical development. The loss of Arhgef7 results in an extensive loss of axons in cultured neurons and in the developing cortex. Arhgef7 is a guanine-nucleotide exchange factor (GEF) for Cdc42, a GTPase that has a central role in directing the formation of axons during brain development. However, active Cdc42 was not able to rescue the knockdown of Arhgef7. We show that Arhgef7 interacts with the GTPase TC10 that is closely related to Cdc42. Expression of active TC10 can restore the ability to extend axons in Arhgef7-deficient neurons. Our results identify an essential role of Arhgef7 during neuronal development that promotes axon formation upstream of TC10.
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Affiliation(s)
- Alejandro López Tobón
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany.,Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy.,European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Megalakshmi Suresh
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany
| | - Jing Jin
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany.,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany
| | - Alessandro Vitriolo
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy.,European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Thorben Pietralla
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany
| | - Kerry Tedford
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Leipziger Str. 44, 39120, Magdeburg, 39120, Germany
| | - Michael Bossenz
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Leipziger Str. 44, 39120, Magdeburg, 39120, Germany
| | - Kristina Mahnken
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany
| | - Friedemann Kiefer
- Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany.,Max-Planck-Institute for Molecular Biomedicine, Mammalian cell signaling laboratory, Röntgenstr. 20, D-48149, Münster, Germany.,European Institute for Molecular Imaging, Westfälische Wilhelms-Universität, Waldeyerstr. 15, D-48149, Münster, Germany
| | - Giuseppe Testa
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy.,European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Klaus-Dieter Fischer
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Leipziger Str. 44, 39120, Magdeburg, 39120, Germany
| | - Andreas W Püschel
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, Schloßplatz 5, D-48149, Münster, Germany. .,Cells-in-Motion Cluster of Excellence, University of Münster, D-48149, Münster, Germany.
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25
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Mao F, Lei J, Enoch O, Wei M, Zhao C, Quan Y, Yu W. Quantitative proteomics of Bombyx mori after BmNPV challenge. J Proteomics 2018; 181:142-151. [PMID: 29674014 DOI: 10.1016/j.jprot.2018.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/30/2018] [Accepted: 04/04/2018] [Indexed: 01/07/2023]
Abstract
The domesticated silkworm is an ideal and economic insect model that plays crucial roles in sericulture and bioreactor. Bombyx mori nucleopolyhedrovirus (BmNPV) is not only an infectious pathogen to B. mori, but also an efficient vector expressing recombinant proteins. Although, the proteomics of silkworm and BmN cell membrane lipid raft towards BmNPV infection had been investigated, proteome results of BmN cells upon BmNPV challenge currently remain ambiguous. In order to explore the interaction between silkworm and BmNPV, we analyzed several pivotal processes of BmNPV infected BmN cell by quantitative mass spectrometry. Our study indicated that a total of 4205 identified proteins, among which 4194 were with quantitative level. Concretely, during BmNPV infection, several transcription factors and epigenetically modified proteins showed substantially different abundance levels. Especially, proteins with binding activity, displayed significant changes in their molecular functions. Disabled non-homologous end joining by BmNPV reflects irreversible breakage of DNA. Nevertheless, highly abundant superoxide dismutase suggests that the cellular defense system is persistently functional in maintaining biochemical homeostasis. Our comparative and quantitative proteomics will be helpful to unravel the dynamics of B.mori after BmNPV infection and could provide new insights to decipher the mechanism of interaction between BmN cell and BmNPV.
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Affiliation(s)
- Fuxiang Mao
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang Province, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, Zhejiang Province, PR China
| | - Jihai Lei
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang Province, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, Zhejiang Province, PR China
| | - Obeng Enoch
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang Province, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, Zhejiang Province, PR China
| | - Ming Wei
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang Province, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, Zhejiang Province, PR China
| | - Cui Zhao
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang Province, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, Zhejiang Province, PR China
| | - Yanping Quan
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang Province, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, Zhejiang Province, PR China
| | - Wei Yu
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang Province, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, Zhejiang Province, PR China.
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26
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Shang W, Jiang Y, Boettcher M, Ding K, Mollenauer M, Liu Z, Wen X, Liu C, Hao P, Zhao S, McManus MT, Wei L, Weiss A, Wang H. Genome-wide CRISPR screen identifies FAM49B as a key regulator of actin dynamics and T cell activation. Proc Natl Acad Sci U S A 2018; 115:E4051-60. [PMID: 29632189 DOI: 10.1073/pnas.1801340115] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Despite decades of research, mechanisms controlling T cell activation remain only partially understood, which hampers T cell-based immune cancer therapies. Here, we performed a genome-wide CRISPR screen to search for genes that regulate T cell activation. Our screen confirmed many of the known regulators in proximal T cell receptor signaling and, importantly, also uncovered a previously uncharacterized regulator, FAM49B (family with sequence similarity 49 member B). FAM49B deficiency led to hyperactivation of Jurkat T cells following T cell receptor stimulation, as indicated by enhancement of CD69 induction, PAK phosphorylation, and actin assembly. FAM49B directly interacted with the active form of the small GTPase Rac, and genetic disruption of the FAM49B-Rac interaction compromised FAM49B function. Thus, FAM49B inhibits T cell activation by repressing Rac activity and modulating cytoskeleton reorganization.
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27
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Guo L, Zhang Y, Ma M, Liu Q, Zhang Y, Peng Y, Liu J. Crystallization of the rice immune receptor RGA5A_S with the rice blast fungus effector AVR1-CO39 prepared via mixture and tandem strategies. Acta Crystallogr F Struct Biol Commun 2018; 74:262-267. [PMID: 29633975 PMCID: PMC5894111 DOI: 10.1107/s2053230x18003618] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/01/2018] [Indexed: 02/07/2023] Open
Abstract
RGA5 is a component of the Pia resistance-protein pair (RGA4/RGA5) from Oryza sativa L. japonica. It acts as an immune receptor that directly recognizes the effector AVR1-CO39 from Magnaporthe oryzae via a C-terminal non-LRR domain (RGA5A_S). The interaction between RGA5A_S and AVR1-CO39 relieves the repression of RGA4, leading to effector-independent cell death. To determine the structure of the complex of RGA5A_S and AVR1-CO39 and to understand the details of this interaction, the complex was prepared by fusing the proteins together, by mixing them in vitro or by co-expressing them in one host cell. Samples purified via the first two strategies were crystallized under two different conditions. A mixture of AVR1-CO39 and RGA5A_S (complex I) crystallized in 1.1 M ammonium tartrate dibasic, 0.1 M sodium acetate-HCl pH 4.6, while crystals of the fusion complex RGA5A_S-TEV-AVR1-CO39 (complex II) were grown in 2 M NaCl. The crystal of complex I belonged to space group P3121, with unit-cell parameters a = b = 66.2, c = 108.8 Å, α = β = 90, γ = 120°. The crystals diffracted to a Bragg spacing of 2.4 Å, and one molecule each of RGA5A_S and AVR1-CO39 were present in the asymmetric unit of the initial model. The crystal of complex II belonged to space group I4, with unit-cell parameters a = b = 137.4, c = 66.2 Å, α = β = γ = 90°. The crystals diffracted to a Bragg spacing of 2.72 Å, and there were two molecules of RGA5A_S and two molecules of AVR1-CO39 in the asymmetric unit of the initial model. Further structural characterization of the interaction between RGA5A_S and AVR1-CO39 will lead to a better understanding of the mechanism underlying effector recognition by R proteins.
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Affiliation(s)
- Liwei Guo
- Key Laboratory of Pest Monitoring and Green Management, MOA and College of Plant Protection, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
| | - Yikun Zhang
- Key Laboratory of Pest Monitoring and Green Management, MOA and College of Plant Protection, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
| | - Mengqi Ma
- Key Laboratory of Pest Monitoring and Green Management, MOA and College of Plant Protection, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
| | - Qiang Liu
- Key Laboratory of Pest Monitoring and Green Management, MOA and College of Plant Protection, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
| | - Yanan Zhang
- Key Laboratory of Pest Monitoring and Green Management, MOA and College of Plant Protection, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
| | - Youliang Peng
- Key Laboratory of Pest Monitoring and Green Management, MOA and College of Plant Protection, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
- State Key Laboratory of Agrobiotechnology, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
| | - Junfeng Liu
- Key Laboratory of Pest Monitoring and Green Management, MOA and College of Plant Protection, China Agricultural University, No. 2 Yunamingyuanxilu, Beijing 100193, People’s Republic of China
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28
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Montero JC, Seoane S, García-Alonso S, Pandiella A. Multisite phosphorylation of P-Rex1 by protein kinase C. Oncotarget 2018; 7:77937-77949. [PMID: 27788493 PMCID: PMC5363633 DOI: 10.18632/oncotarget.12846] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/12/2016] [Indexed: 02/07/2023] Open
Abstract
P-Rex proteins are guanine nucleotide exchange factors (GEFs) that act on the Rho/Rac family of GTP binding proteins. The activity of P-Rex proteins is regulated by several extracellular stimuli. In fact, activation of growth factor receptors has been reported to activate a phosphorylation/dephosphorylation cycle of P-Rex1. Such cycle includes dephosphorylation of serines 313 and 319 which negatively regulate the GEF activity of P-Rex1, together with phosphorylation of serines 605 and 1169 which favour P-Rex1 GEF activity. However, the kinases that regulate phosphorylation at these different regulatory sites are largely unknown. Here we have investigated the potential regulatory action of several kinases on the phosphorylation of P-Rex1 at S313, S319, S605 and S1169. We show that activation of protein kinase C (PKC) caused phosphorylation of S313, S319 and S1169. Activation of growth factor receptors induced phosphorylation of S1169 through a mechanism that was independent of PKC, indicating that distinct kinases and mechanisms control the phosphorylation of P-Rex1 at different regulatory serines. Genetic and biochemical studies confirmed that the PKC isoform PKCδ was able to directly phosphorylate P-Rex1 at S313. Functional studies using cells with very low endogenous P-Rex1 expression, transfected with wild type P-Rex1 or a mutant form in which S313 was substituted by alanine, indicated that phosphorylation at that residue negatively regulated P-Rex1 exchange activity. We suggest that control of P-Rex1 activity depends on a highly dynamic interplay among distinct signalling routes and its multisite phosphorylation is controlled by the action of different kinases.
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Affiliation(s)
- Juan Carlos Montero
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, Spain
| | - Samuel Seoane
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, Spain
| | - Sara García-Alonso
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, Spain
| | - Atanasio Pandiella
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, Spain
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De P, Carlson JH, Jepperson T, Willis S, Leyland-Jones B, Dey N. RAC1 GTP-ase signals Wnt-beta-catenin pathway mediated integrin-directed metastasis-associated tumor cell phenotypes in triple negative breast cancers. Oncotarget 2017; 8:3072-103. [PMID: 27902969 DOI: 10.18632/oncotarget.13618] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/27/2016] [Indexed: 12/21/2022] Open
Abstract
The acquisition of integrin-directed metastasis-associated (ID-MA) phenotypes by Triple-Negative Breast Cancer (TNBC) cells is caused by an upregulation of the Wnt-beta-catenin pathway (WP). We reported that WP is one of the salient genetic features of TNBC. RAC-GTPases, small G-proteins which transduce signals from cell surface proteins including integrins, have been implicated in tumorigenesis and metastasis by their role in essential cellular functions like motility. The collective percentage of alteration(s) in RAC1 in ER+ve BC was lower as compared to ER-ve BC (35% vs 57%) (brca/tcga/pub2015). High expression of RAC1 was associated with poor outcome for RFS with HR=1.48 [CI: 1.15-1.9] p=0.0019 in the Hungarian ER-veBC cohort. Here we examined how WP signals are transduced via RAC1 in the context of ID-MA phenotypes in TNBC. Using pharmacological agents (sulindac sulfide), genetic tools (beta-catenin siRNA), WP modulators (Wnt-C59, XAV939), RAC1 inhibitors (NSC23766, W56) and WP stimulations (LWnt3ACM, Wnt3A recombinant) in a panel of 6-7 TNBC cell lines, we studied fibronectin-directed (1) migration, (2) matrigel invasion, (3) RAC1 and Cdc42 activation, (4) actin dynamics (confocal microscopy) and (5) podia-parameters. An attenuation of WP, which (a) decreased cellular levels of beta-catenin, as well as its nuclear active-form, (b) decreased fibronectin-induced migration, (c) decreased invasion, (d) altered actin dynamics and (e) decreased podia-parameters was successful in blocking fibronectin-mediated RAC1/Cdc42 activity. Both Wnt-antagonists and RAC1 inhibitors blocked fibronectin-induced RAC1 activation and inhibited the fibronectin-induced ID-MA phenotypes following specific WP stimulation by LWnt3ACM as well as Wnt3A recombinant protein. To test a direct involvement of RAC1-activation in WP-mediated ID-MA phenotypes, we stimulated brain-metastasis specific MDA-MB231BR cells with LWnt3ACM. LWnt3ACM-stimulated fibronectin-directed migration was blocked by RAC1 inhibition in MDA-MB231BR cells. In the light of our previous report that WP upregulation causes ID-MA phenotypes in TNBC tumor cells, here we provide the first mechanism based evidence to demonstrate that WP upregulation signals ID-MA tumor cell phenotypes in a RAC1-GTPase dependent manner involving exchange-factors like TIAM1 and VAV2. Our study demonstrates for the first time that beta-catenin-RAC1 cascade signals integrin-directed metastasis-associated tumor cell phenotypes in TNBC.
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Deng Q, Tian YX, Liang J. Mangiferin inhibits cell migration and invasion through Rac1/WAVE2 signalling in breast cancer. Cytotechnology 2018; 70:593-601. [PMID: 29455393 DOI: 10.1007/s10616-017-0140-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 09/02/2017] [Indexed: 01/09/2023] Open
Abstract
Breast tumour progression results from the advancement of the disease to a metastatic phenotype. Rac1 and Cdc42 belong to the Rho family of genes that, together with their downstream effectors, Wiskott-Aldrich Syndrome protein-family verprolin-homologous protein 2 (WAVE2) and Arp2/3, assume a vital part in cytoskeletal rearrangement and the arrangement of film projections that advance malignant cell relocation and invasion. Mangiferin is a characteristic polyphenolic compound from Mangifera indica L. (Anacardiaceae), ordinarily referred to as mango, that is consumed worldwide as a natural product, including culinary and seasoning applications. Mangiferin delays breast malignancy development and progression by inhibiting different signalling pathways required in mitogenic signalling and metastatic progression. Studies were performed to analyse the impact of mangiferin on Rac1/WAVE2 flagging, relocation and invasion in highly metastatic human MDA-MB-231 mammary cells. Additional studies led to the observation that comparative treatment with mangiferin caused marked reduction in tumour cell movement and invasion. Taken together, these discoveries demonstrate that mangiferin treatment adequately hinders Rac1/WAVE2 flagging and diminishes metastatic phenotypic expression in malignant mammary cells, indicating that mangiferin may provide a benefit as a novel restorative approach in the treatment of metastatic breast cancer.
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McGowan SE, McCoy DM. Platelet-derived growth factor receptor-α and Ras-related C3 botulinum toxin substrate-1 regulate mechano-responsiveness of lung fibroblasts. Am J Physiol Lung Cell Mol Physiol 2017; 313:L1174-L1187. [PMID: 28775097 DOI: 10.1152/ajplung.00185.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/27/2017] [Accepted: 07/27/2017] [Indexed: 12/23/2022] Open
Abstract
Platelet-derived growth factor (PDGF)-A, which only signals through PDGF-receptor-α (PDGFR-α), is required for secondary alveolar septal formation. Although PDGFR-α distinguishes mesenchymal progenitor cells during the saccular stage, PDGFR-α-expressing alveolar cells persist through adulthood. PDGF-A sustains proliferation, limits apoptosis, and maintains α-smooth muscle actin (α-SMA)-containing alveolar cells, which congregate at the alveolar entry ring at postnatal day (P)12. PDGFR-α-expressing, α-SMA-containing alveolar cells redistribute in the elongating septum, suggesting that they migrate to the alveolar entry rings, where mechanical tension is higher. We hypothesized that PDGFR-α and Ras-related C3 botulinum toxin substrate 1(Rac1) are required for mechanosensitive myofibroblast migration. Spreading of PDGFR-α-deficient lung fibroblasts was insensitive to increased rigidity, and their migration was not reduced by Rac1-guanine exchange factor (GEF)-inhibition. PDGFR-α-expressing fibroblasts migrated toward stiffer regions within two-dimensional substrates by increasing migrational persistence (durotaxis). Using a Förster resonance energy transfer (FRET) biosensor for Rac1-GTP, we observed that PDGFR-α was required for fibroblast Rac1 responsiveness to stiffness within a three-dimensional collagen substrate, which by itself increased Rac1-FRET. Rho-GTPase stabilized, whereas Rac1-GTPase increased the turnover of focal adhesions. Under conditions that increased Rac1-GTP, PDGFR-α signaled through both phosphoinositide-3-kinase (PIK) or Src to engage the Rac1 GEF dedicator of cytokinesis-1 (Dock180) and p21-activated-kinase interacting exchange factor-β (βPIX). In cooperation with collagen fibers, these signaling pathways may guide fibroblasts toward the more rigid alveolar entry ring during secondary septation. Because emphysema and interstitial fibrosis disrupt the parenchymal mechanical continuum, understanding how mechanical factors regulate fibroblast migration could elicit strategies for alveolar repair and regeneration.
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Affiliation(s)
- Stephen E McGowan
- Department of Veterans Affairs Research Service and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Diann M McCoy
- Department of Veterans Affairs Research Service and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
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Srijakotre N, Man J, Ooms LM, Lucato CM, Ellisdon AM, Mitchell CA. P-Rex1 and P-Rex2 RacGEFs and cancer. Biochem Soc Trans. 2017;45:963-977. [PMID: 28710285 DOI: 10.1042/bst20160269] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 12/15/2022]
Abstract
Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger (P-Rex) proteins are RacGEFs that are synergistically activated by phosphatidylinositol 3,4,5-trisphosphate and Gβγ subunits of G-protein-coupled receptors. P-Rex1 and P-Rex2 share similar amino acid sequence homology, domain structure, and catalytic function. Recent evidence suggests that both P-Rex proteins may play oncogenic roles in human cancers. P-Rex1 and P-Rex2 are altered predominantly via overexpression and mutation, respectively, in various cancer types, including breast cancer, prostate cancer, and melanoma. This review compares the similarities and differences between P-Rex1 and P-Rex2 functions in human cancers in terms of cellular effects and signalling mechanisms. Emerging clinical data predict that changes in expression or mutation of P-Rex1 and P-Rex2 may lead to changes in tumour outcome, particularly in breast cancer and melanoma.
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Kazanietz MG, Barrio-Real L, Casado-Medrano V, Baker MJ, Lopez-Haber C. The P-Rex1/Rac signaling pathway as a point of convergence for HER/ErbB receptor and GPCR responses. Small GTPases 2016; 9:297-303. [PMID: 27588611 DOI: 10.1080/21541248.2016.1221273] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Guanine nucleotide Exchange Factors (GEFs) are responsible for mediating GDP/GTP exchange for specific small G proteins, such as Rac. There has been substantial evidence for the involvement of Rac-GEFs in the control of cancer cell migration and metastatic progression. We have previously established that the Rac-GEF P-Rex1 is a mediator of actin cytoskeleton rearrangements and cell motility in breast cancer cells downstream of HER/ErbB receptors and the G-Protein Coupled Receptor (GPCR) CXCR4. P-Rex1 is highly expressed in luminal A and B breast cancer compared to normal mammary tissue, whereas expression is very low in basal breast cancer, and its expression correlates with the appearance of metastasis in patients. Here, we discuss the involvement of P-Rex1 as an effector of oncogenic/metastatic receptors in breast cancer and underscore its relevance in the convergence of receptor-triggered motile signals. In addition, we provide an overview of our recent findings describing a cross-talk between HER/ErbB receptors and CXCR4, and how this impacts on the activation of P-Rex1/Rac1 signaling, as well as highlight challenges that lie ahead. We propose a model in which P-Rex1 acts as a crucial node for the integration of upstream inputs from HER/ErbB receptors and CXCR4 in luminal breast cancer cells.
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Affiliation(s)
- Marcelo G Kazanietz
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Laura Barrio-Real
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Victoria Casado-Medrano
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Martin J Baker
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
| | - Cynthia Lopez-Haber
- a Department of Systems Pharmacology and Translational Therapeutics , Perelman School of Medicine, University of Pennsylvania , Philadelphia , PA , USA
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Barrows D, He JZ, Parsons R. PREX1 Protein Function Is Negatively Regulated Downstream of Receptor Tyrosine Kinase Activation by p21-activated Kinases (PAKs). J Biol Chem 2016; 291:20042-54. [PMID: 27481946 DOI: 10.1074/jbc.m116.723882] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Indexed: 12/15/2022] Open
Abstract
Downstream of receptor tyrosine kinase and G protein-coupled receptor (GPCR) stimulation, the phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchange factor (PREX) family of guanine nucleotide exchange factors (GEFs) activates Rho GTPases, leading to important roles for PREX proteins in numerous cellular processes and diseases, including cancer. PREX1 and PREX2 GEF activity is activated by the second messengers PIP3 and Gβγ, and further regulation of PREX GEF activity occurs by phosphorylation. Stimulation of receptor tyrosine kinases by neuregulin and insulin-like growth factor 1 (IGF1) leads to the phosphorylation of PREX1; however, the kinases that phosphorylate PREX1 downstream of these ligands are not known. We recently reported that the p21-activated kinases (PAKs), which are activated by GTP-bound Ras-related C3 botulinum toxin substrate 1 (Rac1), mediate the phosphorylation of PREX2 after insulin receptor activation. Here we show that certain phosphorylation events on PREX1 after insulin, neuregulin, and IGF1 treatment are PAK-dependent and lead to a reduction in PREX1 binding to PIP3 Like PREX2, PAK-mediated phosphorylation also negatively regulates PREX1 GEF activity. Furthermore, the onset of PREX1 phosphorylation was delayed compared with the phosphorylation of AKT, supporting a model of negative feedback downstream of PREX1 activation. We also found that the phosphorylation of PREX1 after isoproterenol and prostaglandin E2-mediated GPCR activation is partially PAK-dependent and likely also involves protein kinase A, which is known to reduce PREX1 function. Our data point to multiple mechanisms of PREX1 negative regulation by PAKs within receptor tyrosine kinase and GPCR-stimulated signaling pathways that have important roles in diseases such as diabetes and cancer.
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Affiliation(s)
- Douglas Barrows
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029 and the Department of Pharmacology, Columbia University, New York, New York 10032
| | - John Z He
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029 and
| | - Ramon Parsons
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029 and
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Liu HJ, Ooms LM, Srijakotre N, Man J, Vieusseux J, Waters JE, Feng Y, Bailey CG, Rasko JEJ, Price JT, Mitchell CA. PtdIns(3,4,5)P3-dependent Rac Exchanger 1 (PREX1) Rac-Guanine Nucleotide Exchange Factor (GEF) Activity Promotes Breast Cancer Cell Proliferation and Tumor Growth via Activation of Extracellular Signal-regulated Kinase 1/2 (ERK1/2) Signaling. J Biol Chem 2016; 291:17258-70. [PMID: 27358402 DOI: 10.1074/jbc.m116.743401] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Indexed: 12/20/2022] Open
Abstract
PtdIns(3,4,5)P3-dependent Rac exchanger 1 (PREX1) is a Rac-guanine nucleotide exchange factor (GEF) overexpressed in a significant proportion of human breast cancers that integrates signals from upstream ErbB2/3 and CXCR4 membrane surface receptors. However, the PREX1 domains that facilitate its oncogenic activity and downstream signaling are not completely understood. We identify that ERK1/2 MAPK acts downstream of PREX1 and contributes to PREX1-mediated anchorage-independent cell growth. PREX1 overexpression increased but its shRNA knockdown decreased ERK1/2 phosphorylation in response to EGF/IGF-1 stimulation, resulting in induction of the cell cycle regulators cyclin D1 and p21(WAF1/CIP1) PREX1-mediated ERK1/2 phosphorylation, anchorage-independent cell growth, and cell migration were suppressed by inhibition of MEK1/2/ERK1/2 signaling. PREX1 overexpression reduced staurosporine-induced apoptosis whereas its shRNA knockdown promoted apoptosis in response to staurosporine or the anti-estrogen drug tamoxifen. Expression of wild-type but not GEF-inactive PREX1 increased anchorage-independent cell growth. In addition, mouse xenograft studies revealed that expression of wild-type but not GEF-dead PREX1 resulted in the formation of larger tumors that displayed increased phosphorylation of ERK1/2 but not AKT. The impaired anchorage-independent cell growth, apoptosis, and ERK1/2 signaling observed in stable PREX1 knockdown cells was restored by expression of wild-type but not GEF-dead-PREX1. Therefore, PREX1-Rac-GEF activity is critical for PREX1-dependent anchorage-independent cell growth and xenograft tumor growth and may represent a possible therapeutic target for breast cancers that exhibit PREX1 overexpression.
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Affiliation(s)
- Heng-Jia Liu
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Lisa M Ooms
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Nuthasuda Srijakotre
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Joey Man
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Jessica Vieusseux
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - JoAnne E Waters
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Yue Feng
- the Centenary Institute of Cancer Medicine and Cell Biology, New South Wales 2050, Australia
| | - Charles G Bailey
- the Centenary Institute of Cancer Medicine and Cell Biology, New South Wales 2050, Australia, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - John E J Rasko
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia, Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050, Australia, and
| | - John T Price
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia, the Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Victoria 8001, Australia
| | - Christina A Mitchell
- From the Cancer Program, Monash Biomedicine Discovery Institute, and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia,
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Bhattacharjee P, Paul S, Bhattacharjee P. Risk of occupational exposure to asbestos, silicon and arsenic on pulmonary disorders: Understanding the genetic-epigenetic interplay and future prospects. Environ Res 2016; 147:425-434. [PMID: 26966890 DOI: 10.1016/j.envres.2016.02.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 02/11/2016] [Accepted: 02/28/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND Epidemiological studies suggest strong association of lung disorders with occupational exposure to asbestos, silicon and arsenic. The chronic occupational exposure primarily through inhalation results in adverse outcome on the respiratory tract which may also be fatal. Although several mechanisms have attributed towards these diseases; the molecular pathogenesis is still unknown. OBJECTIVE In this review, we investigated the plausible molecular mechanism based on current research that may identify the genetic and epigenetic susceptibility of respiratory disorders upon such occupational exposures in humans. METHODS We considered genetic variants and epigenetic alterations associated with pulmonary exposure hazards leading to asbestosis, silicosis and arsenicosis. Our review is stringently based on the literatures available through peer-reviewed articles mostly published in the last 10 years. Relevant search were conducted using keywords like "occupational lung disorders" along with "asbestos", "silicon" and "arsenic". RESULTS Till September 2015, pubmed search yielded approximately 780 articles relating to asbestos exposure; 240 articles for silicon exposure and 60 articles for arsenic exposure. Extensive screening for genetic and epigenetic factors identified certain genes and related pathways that are important to determine the susceptibility of an individual towards such occupational exposure. CONCLUSION The link between genotype and phenotype and its association with disease susceptibility is very complex in nature due to several factors like person's environment, lifestyle and nutritional status. The epigenome is dynamic as well as reversible and can be reshaped further by certain dietary components throughout its life. In the present review, we have addressed the role of molecular pathogenesis of occupational lung diseases based on the genetic variability and epigenetic alterations and also attempted to highlight the promising aspect of dietary interventions to counter toxic outcomes upon occupational exposure to asbestos, silicon or arsenic.
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Affiliation(s)
- Pritha Bhattacharjee
- Department of Environmental Science, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, India
| | - Somnath Paul
- Division of Molecular Genetics, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata 700032, India
| | - Pritha Bhattacharjee
- Department of Environmental Science, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, India.
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Lissanu Deribe Y. Interplay between PREX2 mutations and the PI3K pathway and its effect on epigenetic regulation of gene expression in NRAS-mutant melanoma. Small GTPases 2016; 7:178-85. [PMID: 27111337 DOI: 10.1080/21541248.2016.1178366] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PREX2 is a PTEN interacting protein that is significantly mutated in melanoma and pancreatic ductal adenocarcinoma. Recently, we reported the mechanistic basis of melanomagenesis by PREX2 mutations. Truncating PREX2 mutations activate its guanine nucleotide exchange factor activity for its substrate RAC1. This leads to increased PI3K/AKT signaling associated with reduced DNA methylation and increased cell proliferation in NRAS-mutant melanoma. Here, we provide additional data that indicates a reciprocal regulation of PREX2 by PTEN whereby loss of PTEN results in a dramatic increase in expression of PREX2 at the protein level. Pharmacologic studies revealed destabilization of PREX2 by inhibition of PI3K/AKT signaling. Additionally, we provide data to show a selective decrease in a particular histone mark, H4 Lys20 trimethylation, in cells expressing PREX2 (E824*) truncating mutation globally and at the imprint control region of CDKN1C (also known as p57) and IGF2. The decrease in H4K20 trimethylation coupled with DNA hypomethylation at this particular locus is associated with genomic imprinting and regulation of expression of p57 and IGF2. Taken together, these results demonstrate the complex signaling mechanisms that involve PREX2, PI3K/AKT/PTEN and downstream epigenetic machinery to deregulate expression of key cell cycle regulators.
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Affiliation(s)
- Yonathan Lissanu Deribe
- a Department of Genomic Medicine , The University of Texas MD Anderson Cancer Center , Houston , TX , USA
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Cash JN, Davis EM, Tesmer JJG. Structural and Biochemical Characterization of the Catalytic Core of the Metastatic Factor P-Rex1 and Its Regulation by PtdIns(3,4,5)P3. Structure 2016; 24:730-740. [PMID: 27150042 DOI: 10.1016/j.str.2016.02.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 02/17/2016] [Accepted: 02/23/2016] [Indexed: 11/20/2022]
Abstract
Phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger 1 (P-Rex1) is a Rho guanine nucleotide exchange factor synergistically activated by PIP3 and Gβγ that plays an important role in the metastasis of breast, prostate, and skin cancer, making it an attractive therapeutic target. However, the molecular mechanisms behind P-Rex1 regulation are poorly understood. We determined structures of the P-Rex1 pleckstrin homology (PH) domain bound to the headgroup of PIP3 and resolved that PIP3 binding to the PH domain is required for P-Rex1 activity in cells but not for membrane localization, which points to an allosteric activation mechanism by PIP3. We also determined structures of the P-Rex1 tandem Dbl homology/PH domains in complexes with two of its substrate GTPases, Rac1 and Cdc42. Collectively, this study provides important molecular insights into P-Rex1 regulation and tools for targeting the PIP3-binding pocket of P-Rex1 with a new generation of cancer chemotherapeutic agents.
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Affiliation(s)
- Jennifer N Cash
- Departments of Pharmacology and Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Ellen M Davis
- Departments of Pharmacology and Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - John J G Tesmer
- Departments of Pharmacology and Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA.
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Lissanu Deribe Y. Mechanistic insights into the role of truncating PREX2 mutations in melanoma. Mol Cell Oncol 2016; 3:e1160174. [PMID: 27314100 DOI: 10.1080/23723556.2016.1160174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 12/11/2022]
Abstract
PREX2 is a PTEN binding protein that is significantly mutated in melanoma and pancreatic ductal adenocarcinoma. We recently reported the molecular mechanism of tumorigenesis associated with PREX2 mutations: truncating PREX2 mutations activate its RAC1 guanine nucleotide exchanger activity leading to increased PI3K/AKT signaling and enhanced cell proliferation.
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Affiliation(s)
- Yonathan Lissanu Deribe
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center , Houston, Texas, USA
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40
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Lissanu Deribe Y, Shi Y, Rai K, Nezi L, Amin SB, Wu CC, Akdemir KC, Mahdavi M, Peng Q, Chang QE, Hornigold K, Arold ST, Welch HC, Garraway LA, Chin L. Truncating PREX2 mutations activate its GEF activity and alter gene expression regulation in NRAS-mutant melanoma. Proc Natl Acad Sci U S A 2016; 113:E1296-305. [PMID: 26884185 DOI: 10.1073/pnas.1513801113] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PREX2 (phosphatidylinositol-3,4,5-triphosphate-dependent Rac-exchange factor 2) is a PTEN (phosphatase and tensin homolog deleted on chromosome 10) binding protein that is significantly mutated in cutaneous melanoma and pancreatic ductal adenocarcinoma. Here, genetic and biochemical analyses were conducted to elucidate the nature and mechanistic basis of PREX2 mutation in melanoma development. By generating an inducible transgenic mouse model we showed an oncogenic role for a truncating PREX2 mutation (PREX2(E824)*) in vivo in the context of mutant NRAS. Using integrative cross-species gene expression analysis, we identified deregulated cell cycle and cytoskeleton organization as significantly perturbed biological pathways in PREX2 mutant tumors. Mechanistically, truncation of PREX2 activated its Rac1 guanine nucleotide exchange factor activity, abolished binding to PTEN and activated the PI3K (phosphatidyl inositol 3 kinase)/Akt signaling pathway. We further showed that PREX2 truncating mutations or PTEN deletion induces down-regulation of the tumor suppressor and cell cycle regulator CDKN1C (also known as p57(KIP2)). This down-regulation occurs, at least partially, through DNA hypomethylation of a differentially methylated region in chromosome 11 that is a known regulatory region for expression of the CDKN1C gene. Together, these findings identify PREX2 as a mediator of NRAS-mutant melanoma development that acts through the PI3K/PTEN/Akt pathway to regulate gene expression of a cell cycle regulator.
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Chávez-Vargas L, Adame-García SR, Cervantes-Villagrana RD, Castillo-Kauil A, Bruystens JGH, Fukuhara S, Taylor SS, Mochizuki N, Reyes-Cruz G, Vázquez-Prado J. Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor: EFFECT ON PKA LOCALIZATION AND P-Rex1 SIGNALING. J Biol Chem 2016; 291:6182-99. [PMID: 26797121 DOI: 10.1074/jbc.m115.712216] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 12/15/2022] Open
Abstract
Morphology of migrating cells is regulated by Rho GTPases and fine-tuned by protein interactions and phosphorylation. PKA affects cell migration potentially through spatiotemporal interactions with regulators of Rho GTPases. Here we show that the endogenous regulatory (R) subunit of type I PKA interacts with P-Rex1, a Rac guanine nucleotide exchange factor that integrates chemotactic signals. Type I PKA holoenzyme interacts with P-Rex1 PDZ domains via the CNB B domain of RIα, which when expressed by itself facilitates endothelial cell migration. P-Rex1 activation localizes PKA to the cell periphery, whereas stimulation of PKA phosphorylates P-Rex1 and prevents its activation in cells responding to SDF-1 (stromal cell-derived factor 1). The P-Rex1 DEP1 domain is phosphorylated at Ser-436, which inhibits the DH-PH catalytic cassette by direct interaction. In addition, the P-Rex1 C terminus is indirectly targeted by PKA, promoting inhibitory interactions independently of the DEP1-PDZ2 region. A P-Rex1 S436A mutant construct shows increased RacGEF activity and prevents the inhibitory effect of forskolin on sphingosine 1-phosphate-dependent endothelial cell migration. Altogether, these results support the idea that P-Rex1 contributes to the spatiotemporal localization of type I PKA, which tightly regulates this guanine exchange factor by a multistep mechanism, initiated by interaction with the PDZ domains of P-Rex1 followed by direct phosphorylation at the first DEP domain and putatively indirect regulation of the C terminus, thus promoting inhibitory intramolecular interactions. This reciprocal regulation between PKA and P-Rex1 might represent a key node of integration by which chemotactic signaling is fine-tuned by PKA.
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Affiliation(s)
| | - Sendi Rafael Adame-García
- Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico
| | | | - Alejandro Castillo-Kauil
- Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico
| | | | - Shigetomo Fukuhara
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute (NCVC), Osaka, 565-8565 Japan, and
| | - Susan S Taylor
- Departments of Chemistry and Biochemistry and Pharmacology, University of California San Diego, La Jolla, California 92093
| | - Naoki Mochizuki
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute (NCVC), Osaka, 565-8565 Japan, and
| | - Guadalupe Reyes-Cruz
- Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360 Mexico
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Pan D, Barber MA, Hornigold K, Baker MJ, Toth JM, Oxley D, Welch HCE. Norbin Stimulates the Catalytic Activity and Plasma Membrane Localization of the Guanine-Nucleotide Exchange Factor P-Rex1. J Biol Chem 2016; 291:6359-75. [PMID: 26792863 PMCID: PMC4813545 DOI: 10.1074/jbc.m115.686592] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Indexed: 12/15/2022] Open
Abstract
P-Rex1 is a guanine-nucleotide exchange factor (GEF) that activates the small G protein (GTPase) Rac1 to control Rac1-dependent cytoskeletal dynamics, and thus cell morphology. Three mechanisms of P-Rex1 regulation are currently known: (i) binding of the phosphoinositide second messenger PIP3, (ii) binding of the Gβγ subunits of heterotrimeric G proteins, and (iii) phosphorylation of various serine residues. Using recombinant P-Rex1 protein to search for new binding partners, we isolated the G-protein-coupled receptor (GPCR)-adaptor protein Norbin (Neurochondrin, NCDN) from mouse brain fractions. Coimmunoprecipitation confirmed the interaction between overexpressed P-Rex1 and Norbin in COS-7 cells, as well as between endogenous P-Rex1 and Norbin in HEK-293 cells. Binding assays with purified recombinant proteins showed that their interaction is direct, and mutational analysis revealed that the pleckstrin homology domain of P-Rex1 is required. Rac-GEF activity assays with purified recombinant proteins showed that direct interaction with Norbin increases the basal, PIP3- and Gβγ-stimulated Rac-GEF activity of P-Rex1. Pak-CRIB pulldown assays demonstrated that Norbin promotes the P-Rex1-mediated activation of endogenous Rac1 upon stimulation of HEK-293 cells with lysophosphatidic acid. Finally, immunofluorescence microscopy and subcellular fractionation showed that coexpression of P-Rex1 and Norbin induces a robust translocation of both proteins from the cytosol to the plasma membrane, as well as promoting cell spreading, lamellipodia formation, and membrane ruffling, cell morphologies generated by active Rac1. In summary, we have identified a novel mechanism of P-Rex1 regulation through the GPCR-adaptor protein Norbin, a direct P-Rex1 interacting protein that promotes the Rac-GEF activity and membrane localization of P-Rex1.
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Affiliation(s)
| | | | | | | | | | - David Oxley
- the Mass Spectrometry Facility, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
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