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O'Donoghue L, Smolenski A. Roles of G proteins and their GTPase-activating proteins in platelets. Biosci Rep 2024; 44:BSR20231420. [PMID: 38808367 PMCID: PMC11139668 DOI: 10.1042/bsr20231420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/30/2024] Open
Abstract
Platelets are small anucleate blood cells supporting vascular function. They circulate in a quiescent state monitoring the vasculature for injuries. Platelets adhere to injury sites and can be rapidly activated to secrete granules and to form platelet/platelet aggregates. These responses are controlled by signalling networks that include G proteins and their regulatory guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Recent proteomics studies have revealed the complete spectrum of G proteins, GEFs, and GAPs present in platelets. Some of these proteins are specific for platelets and very few have been characterised in detail. GEFs and GAPs play a major role in setting local levels of active GTP-bound G proteins in response to activating and inhibitory signals encountered by platelets. Thus, GEFs and GAPs are highly regulated themselves and appear to integrate G protein regulation with other cellular processes. This review focuses on GAPs of small G proteins of the Arf, Rab, Ras, and Rho families, as well as of heterotrimeric G proteins found in platelets.
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Affiliation(s)
- Lorna O'Donoghue
- UCD School of Medicine, University College Dublin, UCD Conway Institute, Belfield, Dublin 4, Ireland
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green 123, Dublin 2, Ireland
| | - Albert Smolenski
- UCD School of Medicine, University College Dublin, UCD Conway Institute, Belfield, Dublin 4, Ireland
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green 123, Dublin 2, Ireland
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2
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Shankar S, Chew TW, Chichili VPR, Low BC, Sivaraman J. Structural basis for the distinct roles of non-conserved Pro116 and conserved Tyr124 of BCH domain of yeast p50RhoGAP. Cell Mol Life Sci 2024; 81:216. [PMID: 38740643 PMCID: PMC11090974 DOI: 10.1007/s00018-024-05238-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 04/08/2024] [Accepted: 04/11/2024] [Indexed: 05/16/2024]
Abstract
p50RhoGAP is a key protein that interacts with and downregulates the small GTPase RhoA. p50RhoGAP is a multifunctional protein containing the BNIP-2 and Cdc42GAP Homology (BCH) domain that facilitates protein-protein interactions and lipid binding and the GAP domain that regulates active RhoA population. We recently solved the structure of the BCH domain from yeast p50RhoGAP (YBCH) and showed that it maintains the adjacent GAP domain in an auto-inhibited state through the β5 strand. Our previous WT YBCH structure shows that a unique kink at position 116 thought to be made by a proline residue between alpha helices α6 and α7 is essential for the formation of intertwined dimer from asymmetric monomers. Here we sought to establish the role and impact of this Pro116. However, the kink persists in the structure of P116A mutant YBCH domain, suggesting that the scaffold is not dictated by the proline residue at this position. We further identified Tyr124 (or Tyr188 in HBCH) as a conserved residue in the crucial β5 strand. Extending to the human ortholog, when substituted to acidic residues, Tyr188D or Tyr188E, we observed an increase in RhoA binding and self-dimerization, indicative of a loss of inhibition of the GAP domain by the BCH domain. These results point to distinct roles and impact of the non-conserved and conserved amino acid positions in regulating the structural and functional complexity of the BCH domain.
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Affiliation(s)
- Srihari Shankar
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Ti Weng Chew
- Mechanobiology Institute, National University of Singapore, Singapore, 117411, Singapore
| | | | - Boon Chuan Low
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore.
- Mechanobiology Institute, National University of Singapore, Singapore, 117411, Singapore.
- NUS College, National University of Singapore, Singapore, 138593, Singapore.
| | - J Sivaraman
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore.
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3
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Wong DCP, Pan CQ, Er SY, Thivakar T, Rachel TZY, Seah SH, Chua PJ, Jiang T, Chew TW, Chaudhuri PK, Mukherjee S, Salim A, Aye TA, Koh CG, Lim CT, Tan PH, Bay BH, Ridley AJ, Low BC. The scaffold RhoGAP protein ARHGAP8/BPGAP1 synchronizes Rac and Rho signaling to facilitate cell migration. Mol Biol Cell 2023; 34:ar13. [PMID: 36598812 PMCID: PMC10011724 DOI: 10.1091/mbc.e21-03-0099] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 12/14/2022] [Accepted: 12/21/2022] [Indexed: 01/05/2023] Open
Abstract
Rho GTPases regulate cell morphogenesis and motility under the tight control of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). However, the underlying mechanism(s) that coordinate their spatiotemporal activities, whether separately or together, remain unclear. We show that a prometastatic RhoGAP, ARHGAP8/BPGAP1, binds to inactive Rac1 and localizes to lamellipodia. BPGAP1 recruits the RacGEF Vav1 under epidermal growth factor (EGF) stimulation and activates Rac1, leading to polarized cell motility, spreading, invadopodium formation, and cell extravasation and promotes cancer cell migration. Importantly, BPGAP1 down-regulates local RhoA activity, which influences Rac1 binding to BPGAP1 and its subsequent activation by Vav1. Our results highlight the importance of BPGAP1 in recruiting Vav1 and Rac1 to promote Rac1 activation for cell motility. BPGAP1 also serves to control the timing of Rac1 activation with RhoA inactivation via its RhoGAP activity. BPGAP1, therefore, acts as a dual-function scaffold that recruits Vav1 to activate Rac1 while inactivating RhoA to synchronize both Rho and Rac signaling in cell motility. As epidermal growth factor receptor (EGFR), Vav1, RhoA, Rac1, and BPGAP1 are all associated with cancer metastasis, BPGAP1 could provide a crucial checkpoint for the EGFR-BPGAP1-Vav1-Rac1-RhoA signaling axis for cancer intervention.
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Affiliation(s)
| | | | - Shi Yin Er
- Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117558
| | - T. Thivakar
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Tan Zi Yi Rachel
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Sock Hong Seah
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Pei Jou Chua
- Department of Anatomy, Yong Loo Lin School of Medicine, National University Health System, Singapore 117594
| | - Tingting Jiang
- Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117558
| | - Ti Weng Chew
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | | | - Somsubhro Mukherjee
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Agus Salim
- Melbourne School of Population and Global Health and School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Thike Aye Aye
- Department of Pathology, Singapore General Hospital, Singapore 169856
| | - Cheng Gee Koh
- Division of Molecular Genetics & Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Chwee Teck Lim
- Mechanobiology Institute, National University of Singapore, Singapore 117411
- Department of Biomedical Engineering, National University of Singapore, Singapore 117583
| | - Puay Hoon Tan
- Department of Pathology, Singapore General Hospital, Singapore 169856
| | - Boon Huat Bay
- Department of Anatomy, Yong Loo Lin School of Medicine, National University Health System, Singapore 117594
| | - Anne J. Ridley
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Boon Chuan Low
- Mechanobiology Institute, National University of Singapore, Singapore 117411
- Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117558
- NUS College, National University of Singapore, Singapore 138593
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Structure of the Sec14 domain of Kalirin reveals a distinct class of lipid-binding module in RhoGEFs. Nat Commun 2023; 14:96. [PMID: 36609407 PMCID: PMC9823006 DOI: 10.1038/s41467-022-35678-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 12/16/2022] [Indexed: 01/09/2023] Open
Abstract
Gated entry of lipophilic ligands into the enclosed hydrophobic pocket in stand-alone Sec14 domain proteins often links lipid metabolism to membrane trafficking. Similar domains occur in multidomain mammalian proteins that activate small GTPases and regulate actin dynamics. The neuronal RhoGEF Kalirin, a central regulator of cytoskeletal dynamics, contains a Sec14 domain (KalbSec14) followed by multiple spectrin-like repeats and catalytic domains. Previous studies demonstrated that Kalirin lacking its Sec14 domain fails to maintain cell morphology or dendritic spine length, yet whether and how KalbSec14 interacts with lipids remain unknown. Here, we report the structural and biochemical characterization of KalbSec14. KalbSec14 adopts a closed conformation, sealing off the canonical ligand entry site, and instead employs a surface groove to bind a limited set of lysophospholipids. The low-affinity interactions of KalbSec14 with lysolipids are expected to serve as a general model for the regulation of Rho signaling by other Sec14-containing Rho activators.
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A current overview of RhoA, RhoB, and RhoC functions in vascular biology and pathology. Biochem Pharmacol 2022; 206:115321. [DOI: 10.1016/j.bcp.2022.115321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 11/24/2022]
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Wong DCP, Xiao J, Chew TW, Pan M, Lee CJM, Ang JW, Yow I, Thivakar T, Ackers‐Johnson M, Lee NJW, Foo RS, Kanchanawong P, Low BC. BNIP-2 Activation of Cellular Contractility Inactivates YAP for H9c2 Cardiomyoblast Differentiation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202834. [PMID: 35975420 PMCID: PMC9631078 DOI: 10.1002/advs.202202834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Rho GTPases and Hippo kinases are key regulators of cardiomyoblast differentiation. However, how these signaling axes are coordinated spatiotemporally remains unclear. Here, the central and multifaceted roles of the BCH domain containing protein, BNIP-2, in orchestrating the expression of two key cardiac genes (cardiac troponin T [cTnT] and cardiac myosin light chain [Myl2]) in H9c2 and human embryonic stem cell-derived cardiomyocytes are delineated. This study shows that BNIP-2 mRNA and protein expression increase with the onset of cTnT and Myl2 and promote the alignment of H9c2 cardiomyocytes. Mechanistically, BNIP-2 is required for the inactivation of YAP through YAP phosphorylation and its cytosolic retention. Turbo-ID proximity labeling corroborated by super-resolution analyses and biochemical pulldown data reveals a scaffolding role of BNIP-2 for LATS1 to phosphorylate and inactivate YAP in a process that requires BNIP-2 activation of cellular contractility. The findings identify BNIP-2 as a pivotal signaling scaffold that spatiotemporally integrates RhoA/Myosin II and LATS1/YAP mechanotransduction signaling to drive cardiomyoblast differentiation, by switching the genetic programming from YAP-dependent growth to YAP-silenced differentiation. These findings offer insights into the importance of scaffolding proteins in bridging the gap between mechanical and biochemical signals in cell growth and differentiation and the prospects in translational applications.
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Affiliation(s)
- Darren Chen Pei Wong
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
- Department of Biological SciencesNational University of SingaporeSingapore117558Singapore
| | - Jingwei Xiao
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
| | - Ti Weng Chew
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
| | - Meng Pan
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
| | - Chang Jie Mick Lee
- Genome Institute of SingaporeAgency for ScienceTechnology and ResearchSingapore138672Singapore
| | - Jing Wen Ang
- Department of Biological SciencesNational University of SingaporeSingapore117558Singapore
| | - Ivan Yow
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
| | - T. Thivakar
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
| | - Matthew Ackers‐Johnson
- Genome Institute of SingaporeAgency for ScienceTechnology and ResearchSingapore138672Singapore
- Cardiovascular Research InstituteNational University Healthcare SystemsSingapore117599Singapore
| | - Nicole Jia Wen Lee
- Department of Biological SciencesNational University of SingaporeSingapore117558Singapore
| | - Roger Sik‐Yin Foo
- Genome Institute of SingaporeAgency for ScienceTechnology and ResearchSingapore138672Singapore
- Cardiovascular Research InstituteNational University Healthcare SystemsSingapore117599Singapore
- Department of MedicineYong Loo Lin School of MedicineNational University of SingaporeSingapore117597Singapore
| | - Pakorn Kanchanawong
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
- Department of Biomedical EngineeringNational University of SingaporeSingapore117583Singapore
| | - Boon Chuan Low
- Mechanobiology Institute SingaporeNational University of SingaporeSingapore117411Singapore
- Department of Biological SciencesNational University of SingaporeSingapore117558Singapore
- NUS CollegeNational University of SingaporeSingapore138593Singapore
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Chau JE, Vish KJ, Boggon TJ, Stiegler AL. SH3 domain regulation of RhoGAP activity: Crosstalk between p120RasGAP and DLC1 RhoGAP. Nat Commun 2022; 13:4788. [PMID: 35970859 PMCID: PMC9378701 DOI: 10.1038/s41467-022-32541-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 08/04/2022] [Indexed: 11/10/2022] Open
Abstract
RhoGAP proteins are key regulators of Rho family GTPases and influence a variety of cellular processes, including cell migration, adhesion, and cytokinesis. These GTPase activating proteins (GAPs) downregulate Rho signaling by binding and enhancing the intrinsic GTPase activity of Rho proteins. Deleted in liver cancer 1 (DLC1) is a tumor suppressor and ubiquitously expressed RhoGAP protein; its activity is regulated in part by binding p120RasGAP, a GAP protein for the Ras GTPases. In this study, we report the co-crystal structure of the p120RasGAP SH3 domain bound directly to DLC1 RhoGAP, at a site partially overlapping the RhoA binding site and impinging on the catalytic arginine finger. We demonstrate biochemically that mutation of this interface relieves inhibition of RhoGAP activity by the SH3 domain. These results reveal the mechanism for inhibition of DLC1 RhoGAP activity by p120RasGAP and demonstrate the molecular basis for direct SH3 domain modulation of GAP activity.
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Affiliation(s)
- Jocelyn E Chau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kimberly J Vish
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA.
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Fixing the GAP: the role of RhoGAPs in cancer. Eur J Cell Biol 2022; 101:151209. [DOI: 10.1016/j.ejcb.2022.151209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 01/29/2022] [Accepted: 02/08/2022] [Indexed: 12/12/2022] Open
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