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Comer SP. Turning Platelets Off and On: Role of RhoGAPs and RhoGEFs in Platelet Activity. Front Cardiovasc Med 2022; 8:820945. [PMID: 35071371 PMCID: PMC8770426 DOI: 10.3389/fcvm.2021.820945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/15/2021] [Indexed: 12/15/2022] Open
Abstract
Platelet cytoskeletal reorganisation is a critical component of platelet activation and thrombus formation in haemostasis. The Rho GTPases RhoA, Rac1 and Cdc42 are the primary drivers in the dynamic reorganisation process, leading to the development of filopodia and lamellipodia which dramatically increase platelet surface area upon activation. Rho GTPases cycle between their active (GTP-bound) and inactive (GDP-bound) states through tightly regulated processes, central to which are the guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). GEFs catalyse the dissociation of GDP by inducing changes in the nucleotide binding site, facilitating GTP binding and activating Rho GTPases. By contrast, while all GTPases possess intrinsic hydrolysing activity, this reaction is extremely slow. Therefore, GAPs catalyse the hydrolysis of GTP to GDP, reverting Rho GTPases to their inactive state. Our current knowledge of these proteins is constantly being updated but there is considerably less known about the functionality of Rho GTPase specific GAPs and GEFs in platelets. In the present review, we discuss GAP and GEF proteins for Rho GTPases identified in platelets, their regulation, biological function and present a case for their further study in platelets.
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Affiliation(s)
- Shane P Comer
- ConwaySPHERE Research Group, UCD Conway Institute, University College Dublin, Dublin, Ireland.,School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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2
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Abstract
The Ras homologous (Rho) protein family of GTPases (RhoA, RhoB and RhoC) are the members of the Ras superfamily and regulate cellular processes such as cell migration, proliferation, polarization, adhesion, gene transcription and cytoskeletal structure. Rho GTPases function as molecular switches that cycle between GTP-bound (active state) and GDP-bound (inactive state) forms. Leukaemia-associated RhoGEF (LARG) is a guanine nucleotide exchange factor (GEF) that activates RhoA subfamily GTPases by promoting the exchange of GDP for GTP. LARG is selective for RhoA subfamily GTPases and is an essential regulator of cell migration and invasion. Here, we describe the mechanisms by which LARG is regulated to facilitate the understanding of how LARG mediates functions like cell motility and to provide insight for better therapeutic targeting of these functions.
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Affiliation(s)
- Neda Z. Ghanem
- Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Mānoa, Honolulu, USA,Molecular Biosciences and BioEngineering Graduate Program, University of Hawaii at Mānoa, Honolulu, USA
| | - Michelle L. Matter
- Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Mānoa, Honolulu, USA,Molecular Biosciences and BioEngineering Graduate Program, University of Hawaii at Mānoa, Honolulu, USA
| | - Joe W. Ramos
- Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Mānoa, Honolulu, USA,Molecular Biosciences and BioEngineering Graduate Program, University of Hawaii at Mānoa, Honolulu, USA,CONTACT Joe W. Ramos Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, USA
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Panagopoulos I, Andersen K, Eilert-Olsen M, Zeller B, Munthe-Kaas MC, Buechner J, Osnes LTN, Micci F, Heim S. Therapy-induced Deletion in 11q23 Leading to Fusion of KMT2A With ARHGEF12 and Development of B Lineage Acute Lymphoplastic Leukemia in a Child Treated for Acute Myeloid Leukemia Caused by t(9;11)(p21;q23)/ KMT2A-MLLT3. Cancer Genomics Proteomics 2021; 18:67-81. [PMID: 33419897 DOI: 10.21873/cgp.20242] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/25/2020] [Accepted: 10/27/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND/AIM Fusion of histone-lysine N-methyltransferase 2A gene (KMT2A) with the Rho guanine nucleotide exchange factor 12 gene (ARHGEF12), both located in 11q23, was reported in some leukemic patients. We report a KMT2A-ARHGEF12 fusion occurring during treatment of a pediatric acute myeloid leukemia (AML) with topoisomerase II inhibitors leading to a secondary acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS Multiple genetic analyses were performed on bone marrow cells of a girl initially diagnosed with AML. RESULTS At the time of diagnosis with AML, the t(9;11)(p21;q23)/KMT2A-MLLT3 genetic abnormality was found. After chemotherapy resulting in AML clinical remission, a 2 Mb deletion in 11q23 was found generating a KMT2A-ARHGEF12 fusion gene. When the patient later developed B lineage ALL, a t(14;19)(q32;q13), loss of one chromosome 9, and KMT2A-ARHGEF12 were detected. CONCLUSION The patient sequentially developed AML and ALL with three leukemia-specific genomic abnormalities in her bone marrow cells, two of which were KMT2A-rearrangements.
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Affiliation(s)
- Ioannis Panagopoulos
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway;
| | - Kristin Andersen
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Martine Eilert-Olsen
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Bernward Zeller
- Department of Pediatric Hematology and Oncology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Monica Cheng Munthe-Kaas
- Department of Pediatric Hematology and Oncology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Jochen Buechner
- Department of Pediatric Hematology and Oncology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Liv T N Osnes
- Department of Immunology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Francesca Micci
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Sverre Heim
- Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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Xing XQ, Li B, Xu SL, Liu J, Zhang CF, Yang J. MicroRNA-214-3p Regulates Hypoxia-Mediated Pulmonary Artery Smooth Muscle Cell Proliferation and Migration by Targeting ARHGEF12. Med Sci Monit 2019; 25:5738-5746. [PMID: 31373336 PMCID: PMC6689201 DOI: 10.12659/msm.915709] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/17/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND miR-214-3p has been found to inhibit proliferation and migration in cancer cells. The objective of this study was to determine whether ARHGEF12 is involved in miR-214-3p-mediated suppression of proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). MATERIAL AND METHODS PASMCs were cultured under normoxia or hypoxia. miR-214-3p mimics or inhibitors were transiently transfected into PASMCs. Proliferation, apoptosis, and migration of PASMCs were evaluated using MTT assay, flow cytometry, and Boyden chamber apparatus. Western blot analysis was used to examine expression of Rho guanine nucleotide exchange factor 12 (ARHGEF12), c-fos, c-jun, and caspase-3. Luciferase reporter assay was used to test the direct regulation of miR-214-3p on the 3'-untranslated region (UTR) of ARHGEF12. RESULTS miR-214-3p was significantly upregulated in hypoxia-treated PASMCs. Knockdown of miR-214-3p significantly attenuated hypoxia-induced proliferation and migration in PASMCs and promoted apoptosis, whereas this effect was aggravated by overexpression of miR-214-3p. In addition, dual-luciferase reporter assay demonstrated that ARHGEF12 is a direct target gene of miR-214-3p. The protein levels of ARHGEF12 were downregulated after knockdown of miR-214-3p in PASMCs. Rescue experiment results indicated that decreased proliferation of PASMCs resulted from knockdown of miR-214-3p were partially reversed by silencing of ARHGEF12 by siRNA. Furthermore, knockdown of miR-214-3p reduced expression of c-jun and c-fos, but increased expression of caspase-3 in PASMCs under hypoxia. CONCLUSIONS In conclusion, these results indicate that miR-214-3p acts as a novel regulator of hypoxia-induced proliferation and migration by directly targeting ARHGEF12 and dysregulating c-jun and c-fos in PASMCs, and may be a potential therapeutic target for treating pulmonary hypertension.
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Affiliation(s)
- Xi-Qian Xing
- Department of Respiratory Medicine, Fourth Affiliated Hospital of Kunming Medical University, Second People’s Hospital of Yunnan Province, Kunming, Yunnan, P.R. China
| | - Bo Li
- College of Pharmacy, Kunming Medical University, Kunming, Yunnan, P.R. China
| | - Shuang-Lan Xu
- Department of Respiratory Medicine, Fourth Affiliated Hospital of Kunming Medical University, Second People’s Hospital of Yunnan Province, Kunming, Yunnan, P.R. China
| | - Jie Liu
- Department of Respiratory Medicine, Fourth Affiliated Hospital of Kunming Medical University, Second People’s Hospital of Yunnan Province, Kunming, Yunnan, P.R. China
| | - Chun-Fang Zhang
- Department of Respiratory Medicine, Fourth Affiliated Hospital of Kunming Medical University, Second People’s Hospital of Yunnan Province, Kunming, Yunnan, P.R. China
| | - Jiao Yang
- Department of Respiratory Medicine, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, P.R. China
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Qasim H, Karim ZA, Hernandez KR, Lozano D, Khasawneh FT, Alshbool FZ. Arhgef1 Plays a Vital Role in Platelet Function and Thrombogenesis. J Am Heart Assoc 2019; 8:e011712. [PMID: 30994039 PMCID: PMC6512111 DOI: 10.1161/jaha.118.011712] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/25/2019] [Indexed: 01/09/2023]
Abstract
Background Platelets are the cellular mediators of hemostasis and thrombosis, and their function is regulated by a number of molecular mediators, such as small GTP ases. These small GTP ases are themselves regulated by guanine nucleotide exchange factors such as Arhgefs, several of which are found in platelets, including the highly expressed Arhgef1. However, the role of Arhgef1 in platelets has not yet been investigated. Methods and Results We employed mice with genetic deletion of Arhgef1 (ie, Arhgef1-/-) and investigated their platelet phenotype by employing a host of in vivo and in vitro platelet assays. Our results indicate that Arhgef1-/- mice had prolonged carotid artery occlusion and tail bleeding times. Moreover, platelets from these mice exhibited defective aggregation, dense and α granule secretion, α II bβ3 integrin activation, clot retraction and spreading, in comparison to their wild-type littermates. Finally, we also found that the mechanism by which Arhgef1 regulates platelets is mediated in part by a defect in the activation of the RhoA-Rho-associated kinase axis, but not Rap1b. Conclusions Our data demonstrate, for the first time, that Arhgef1 plays a critical role in platelet function, in vitro and in vivo.
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Affiliation(s)
- Hanan Qasim
- Department of Pharmaceutical SciencesSchool of PharmacyThe University of Texas El PasoEl PasoTX
| | - Zubair A. Karim
- Department of Pharmaceutical SciencesSchool of PharmacyThe University of Texas El PasoEl PasoTX
| | - Keziah R. Hernandez
- Department of Pharmaceutical SciencesSchool of PharmacyThe University of Texas El PasoEl PasoTX
| | | | - Fadi T. Khasawneh
- Department of Pharmaceutical SciencesSchool of PharmacyThe University of Texas El PasoEl PasoTX
| | - Fatima Z. Alshbool
- Department of Pharmaceutical SciencesSchool of PharmacyThe University of Texas El PasoEl PasoTX
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Affiliation(s)
- Joseph E. Aslan
- Knight Cardiovascular Institute, School of Medicine, Oregon Health & Science University, Portland, Oregon, USA
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health & Science University, Portland, Oregon, USA
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, Oregon, USA
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Bodmann EL, Krett AL, Bünemann M. Potentiation of receptor responses induced by prolonged binding of Gα 13 and leukemia-associated RhoGEF. FASEB J 2017; 31:3663-3676. [PMID: 28465324 DOI: 10.1096/fj.201700026r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/17/2017] [Indexed: 12/29/2022]
Abstract
Diverse cellular functions are controlled by RhoA-GTPases, which are activated by trimeric G proteins via RhoGEFs, among others. In this study, we focused on the signaling from GPCRs to RhoA via Gα13 and leukemia-associated RhoGEF (LARG). The activation of Gα13 was elucidated in living cells with high temporal and spatial resolution by means of FRET. The inactivation after agonist withdrawal occurred in the same range (t1/2 = 25.3 ± 2.2 s; mean ± sem; n = 22) as described for other Gα proteins. The interaction of Gα13 and LARG and the thereby-induced LARG translocation to the plasma membrane were at least 1 order of magnitude more stable after agonist withdrawal, exceeding Gα13 deactivation in the absence of LARG several fold. Consequently, we observed an almost 100-fold higher agonist sensitivity of the Gα13 LARG interaction compared to the Gα13 activation in the absence of LARG.-Bodmann, E.-L., Krett, A.-L., Bünemann, M. Potentiation of receptor responses induced by prolonged binding of Gα13 and leukemia-associated RhoGEF.
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Affiliation(s)
- Eva-Lisa Bodmann
- Department of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
| | - Anna-Lena Krett
- Department of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
| | - Moritz Bünemann
- Department of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
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