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De Silva E, Hong F, Falet H, Kim H. Filamin A in platelets: Bridging the (signaling) gap between the plasma membrane and the actin cytoskeleton. Front Mol Biosci 2022; 9:1060361. [PMID: 36605989 PMCID: PMC9808056 DOI: 10.3389/fmolb.2022.1060361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
Platelets are anucleate cells that are essential for hemostasis and wound healing. Upon activation of the cell surface receptors by their corresponding extracellular ligands, platelets undergo rapid shape change driven by the actin cytoskeleton; this shape change reaction is modulated by a diverse array of actin-binding proteins. One actin-binding protein, filamin A (FLNA), cross-links and stabilizes subcortical actin filaments thus providing stability to the cell membrane. In addition, FLNA binds the intracellular portion of multiple cell surface receptors and acts as a critical intracellular signaling scaffold that integrates signals between the platelet's plasma membrane and the actin cytoskeleton. This mini-review summarizes how FLNA transduces critical cell signals to the platelet cytoskeleton.
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Affiliation(s)
- Enoli De Silva
- Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Felix Hong
- Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Hervé Falet
- Versiti Blood Research Institute, Milwaukee, WI, United States
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Hugh Kim
- Centre for Blood Research, University of British Columbia, Vancouver, BC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, BC, Canada
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Qu J, Zheng B, Ohuchida K, Feng H, Chong SJF, Zhang X, Liang R, Liu Z, Shirahane K, Mizumoto K, Gong P, Nakamura M. PIK3CB is involved in metastasis through the regulation of cell adhesion to collagen I in pancreatic cancer. J Adv Res 2021; 33:127-140. [PMID: 34603784 PMCID: PMC8463925 DOI: 10.1016/j.jare.2021.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/28/2021] [Accepted: 02/06/2021] [Indexed: 12/15/2022] Open
Abstract
Introduction Pancreatic adenocarcinoma (PAAD) is an aggressive malignancy, with a major mortality resulting from the rapid progression of metastasis. Unfortunately, no effective treatment strategy has been developed for PAAD metastasis to date. Thus, unraveling the mechanisms involved in PAAD metastatic phenotype may facilitate the treatment for PAAD patients. Objectives PIK3CB is an oncogene implicated in cancer development and progression but less is known about whether PIK3CB participates in PAAD metastasis. Therefore, the objective of this study is to explore the mechanism(s) of PIK3CB in PAAD metastasis. Methods In our study, we examined the PIK3CB expression pattern using bioinformatic analysis and clinical material derived from patients with PAAD. Subsequently, a series of biochemical experiments were conducted to investigate the role of PIK3CB as potential mechanism(s) underlying PAAD metastasis in vivo using nude mice and in vitro using cell lines. Results We observed that PIK3CB was involved in PAAD progression. Notably, we identified that PIK3CB was involved in PAAD metastasis. Downregulation of PIK3CB significantly reduced PAAD metastatic potential in vivo. Furthermore, a series of bioinformatic analyses showed that PIK3CB was involved in cell adhesion in PAAD. Notably, PIK3CB depletion inhibited invasion potential specifically via suppressing cell adhesion to collagen I in PAAD cells. Conclusion Collectively, our findings indicate that PIK3CB is involved in PAAD metastasis through cell-matrix adhesion. We proposed that PIK3CB is a potential therapeutic target for PAAD therapy.
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Affiliation(s)
- Jianhua Qu
- Department of General Surgery & Carson International Cancer Research Center, Shenzhen University General Hospital and Shenzhen University Clinical Medical Academy, Shenzhen, Guangdong 518055, China.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore 117593, Singapore
| | - Biao Zheng
- Department of General Surgery & Carson International Cancer Research Center, Shenzhen University General Hospital and Shenzhen University Clinical Medical Academy, Shenzhen, Guangdong 518055, China.,Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kenoki Ohuchida
- Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.,Advanced Medical Initiatives, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Haimin Feng
- Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | | | - Xianbin Zhang
- Department of General Surgery & Carson International Cancer Research Center, Shenzhen University General Hospital and Shenzhen University Clinical Medical Academy, Shenzhen, Guangdong 518055, China
| | - Rui Liang
- Department of General Surgery & Carson International Cancer Research Center, Shenzhen University General Hospital and Shenzhen University Clinical Medical Academy, Shenzhen, Guangdong 518055, China
| | - Zhong Liu
- Department of General Surgery & Carson International Cancer Research Center, Shenzhen University General Hospital and Shenzhen University Clinical Medical Academy, Shenzhen, Guangdong 518055, China
| | - Kengo Shirahane
- Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Kazuhiro Mizumoto
- Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.,Cancer Center of Kyushu University Hospital, Fukuoka 812-8582, Japan
| | - Peng Gong
- Department of General Surgery & Carson International Cancer Research Center, Shenzhen University General Hospital and Shenzhen University Clinical Medical Academy, Shenzhen, Guangdong 518055, China.,Guangdong Key Laboratory of Regional Immunity and Diseases, Shenzhen University Health Science Center, Shenzhen, Guangdong 518060, China
| | - Masafumi Nakamura
- Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Phosphoinositide 3-kinases in platelets, thrombosis and therapeutics. Biochem J 2021; 477:4327-4342. [PMID: 33242335 DOI: 10.1042/bcj20190402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/20/2020] [Accepted: 11/04/2020] [Indexed: 12/13/2022]
Abstract
Our knowledge on the expression, regulation and roles of the different phosphoinositide 3-kinases (PI3Ks) in platelet signaling and functions has greatly expanded these last twenty years. Much progress has been made in understanding the roles and regulations of class I PI3Ks which produce the lipid second messenger phosphatidylinositol 3,4,5 trisphosphate (PtdIns(3,4,5)P3). Selective pharmacological inhibitors and genetic approaches have allowed researchers to generate an impressive amount of data on the role of class I PI3Kα, β, δ and γ in platelet activation and in thrombosis. Furthermore, platelets do also express two class II PI3Ks (PI3KC2α and PI3KC2β), thought to generate PtdIns(3,4)P2 and PtdIns3P, and the sole class III PI3K (Vps34), known to synthesize PtdIns3P. Recent studies have started to reveal the importance of PI3KC2α and Vps34 in megakaryocytes and platelets, opening new perspective in our comprehension of platelet biology and thrombosis. In this review, we will summarize previous and recent advances on platelet PI3Ks isoforms. The implication of these kinases and their lipid products in fundamental platelet biological processes and thrombosis will be discussed. Finally, the relevance of developing potential antithrombotic strategies by targeting PI3Ks will be examined.
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Gupta N, Li W, McIntyre TM. Deubiquitinases Modulate Platelet Proteome Ubiquitination, Aggregation, and Thrombosis. Arterioscler Thromb Vasc Biol 2015; 35:2657-66. [PMID: 26471267 DOI: 10.1161/atvbaha.115.306054] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/24/2015] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Platelets express a functional ubiquitin-proteasome system. Mass spectrometry shows that platelets contain several deubiquitinases, but whether these are functional, modulate the proteome, or affect platelet reactivity are unknown. APPROACH AND RESULTS Platelet lysates contained ubiquitin-protein deubiquitinase activity hydrolyzing both Lys48 and Lys63 polyubiquitin conjugates that was suppressed by the chemically unrelated deubiquitinase inhibitors PYR41 and PR619. These inhibitors acutely and markedly increased monoubiquitination and polyubiquitination of the proteome of resting platelets. PYR41 (intravenous, 15 minutes) significantly impaired occlusive thrombosis in FeCl3-damaged carotid arteries, and deubiquitinase inhibition reduced platelet adhesion and retention during high shear flow of whole blood through microfluidic chambers coated with collagen. Total internal reflection microscopy showed that adhesion and spreading in the absence of flow were strongly curtailed by these inhibitors with failure of stable process extension and reduced the retraction of formed clots. Deubiquitinase inhibition also sharply reduced homotypic platelet aggregation in response to not only the incomplete agonists ADP and collagen acting through glycoprotein VI but also to the complete agonist thrombin. Suppressed aggregation was accompanied by curtailed procaspase activating compound-1 binding to activated IIb/IIIa and inhibition of P-selectin translocation to the platelet surface. Deubiquitinase inhibition abolished the agonist-induced spike in intracellular calcium, suppressed Akt phosphorylation, and reduced agonist-stimulated phosphatase and tensin homolog phosphatase phosphorylation. Platelets express the proteasome-associated deubiquitinases USP14 and UCHL5, and selective inhibition of these enzymes by b-AP15 reproduced the inhibitory effect of the general deubiquitinase inhibitors on ex vivo platelet function. CONCLUSIONS Remodeling of the ubiquitinated platelet proteome by deubiquitinases promotes agonist-stimulated intracellular signal transduction and platelet responsiveness.
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Affiliation(s)
- Nilaksh Gupta
- From the Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland, OH; and Department of Molecular Medicine, Case Western Reserve University, Cleveland, OH
| | - Wei Li
- From the Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland, OH; and Department of Molecular Medicine, Case Western Reserve University, Cleveland, OH
| | - Thomas M McIntyre
- From the Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland, OH; and Department of Molecular Medicine, Case Western Reserve University, Cleveland, OH.
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Dbouk HA, Vadas O, Shymanets A, Burke JE, Salamon RS, Khalil BD, Barrett MO, Waldo GL, Surve C, Hsueh C, Perisic O, Harteneck C, Shepherd PR, Harden TK, Smrcka AV, Taussig R, Bresnick AR, Nürnberg B, Williams RL, Backer JM. G protein-coupled receptor-mediated activation of p110β by Gβγ is required for cellular transformation and invasiveness. Sci Signal 2012; 5:ra89. [PMID: 23211529 DOI: 10.1126/scisignal.2003264] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Synergistic activation by heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) and receptor tyrosine kinases distinguishes p110β from other class IA phosphoinositide 3-kinases (PI3Ks). Activation of p110β is specifically implicated in various physiological and pathophysiological processes, such as the growth of tumors deficient in phosphatase and tensin homolog deleted from chromosome 10 (PTEN). To determine the specific contribution of GPCR signaling to p110β-dependent functions, we identified the site in p110β that binds to the Gβγ subunit of G proteins. Mutation of this site eliminated Gβγ-dependent activation of PI3Kβ (a dimer of p110β and the p85 regulatory subunit) in vitro and in cells, without affecting basal activity or phosphotyrosine peptide-mediated activation. Disrupting the p110β-Gβγ interaction by mutation or with a cell-permeable peptide inhibitor blocked the transforming capacity of PI3Kβ in fibroblasts and reduced the proliferation, chemotaxis, and invasiveness of PTEN-null tumor cells in culture. Our data suggest that specifically targeting GPCR signaling to PI3Kβ could provide a therapeutic approach for tumors that depend on p110β for growth and metastasis.
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Affiliation(s)
- Hashem A Dbouk
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Jackson SP, Schoenwaelder SM. Antithrombotic phosphoinositide 3-kinase β inhibitors in humans: a 'shear' delight! J Thromb Haemost 2012; 10:2123-6. [PMID: 22943292 DOI: 10.1111/j.1538-7836.2012.04912.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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A novel membrane-dependent on/off switch mechanism of talin FERM domain at sites of cell adhesion. Cell Res 2012; 22:1533-45. [PMID: 22710802 DOI: 10.1038/cr.2012.97] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The activation of heterodimeric (α/β) integrin transmembrane receptors by cytosolic protein talin is crucial for regulating diverse cell-adhesion-dependent processes, including blood coagulation, tissue remodeling, and cancer metastasis. This process is triggered by the coincident binding of N-terminal FERM (four-point-one-protein/ezrin/radixin/moesin) domain of talin (talin-FERM) to the inner membrane surface and integrin β cytoplasmic tail, but how these binding events are spatiotemporally regulated remains obscure. Here we report the crystal structure of a dormant talin, revealing how a C-terminal talin rod segment (talin-RS) self-masks a key integrin-binding site on talin-FERM via a large interface. Unexpectedly, the structure also reveals a distinct negatively charged surface on talin-RS that electrostatically hinders the talin-FERM binding to the membrane. Such a dual inhibitory topology for talin is consistent with the biochemical and functional data, but differs significantly from a previous model. We show that upon enrichment with phosphotidylinositol-4,5-bisphosphate (PIP2) - a known talin activator, membrane strongly attracts a positively charged surface on talin-FERM and simultaneously repels the negatively charged surface on talin-RS. Such an electrostatic "pull-push" process promotes the relief of the dual inhibition of talin-FERM, which differs from the classic "steric clash" model for conventional PIP2-induced FERM domain activation. These data therefore unravel a new type of membrane-dependent FERM domain regulation and illustrate how it mediates the talin on/off switches to regulate integrin transmembrane signaling and cell adhesion.
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Qian F, Le Breton GC, Chen J, Deng J, Christman JW, Wu D, Ye RD. Role for the guanine nucleotide exchange factor phosphatidylinositol-3,4,5-trisphosphate-dependent rac exchanger 1 in platelet secretion and aggregation. Arterioscler Thromb Vasc Biol 2011; 32:768-77. [PMID: 22207728 DOI: 10.1161/atvbaha.111.243675] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Recent studies have shown a role for Rac1 in regulating platelet functions, but how Rac1 is activated in platelets remains unclear. Phosphatidylinositol-3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) was originally identified in neutrophils that regulates phagocyte functions. We sought to examine whether P-Rex1 plays a role in platelet activation. METHODS AND RESULTS Western blotting showed P-Rex1 expression in mouse and human platelets. Mice lacking P-Rex1 exhibited prolonged bleeding time and increased rebleeding. When challenged with low doses of the G protein-coupled receptor (GPCR) agonists U46619 and thrombin, P-Rex1-/- platelets displayed significantly reduced secretion and aggregation compared with wild-type platelets. Increasing the concentration of these agonists could overcome the defect. Platelet aggregation induced by collagen, a non-GPCR agonist, was also compromised in the absence of P-Rex1. Along with these phenotypic changes were impaired Rac1 activation; reduced ATP secretion; and decreased phosphorylation of Akt, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase in P-Rex1-/- platelets on agonist stimulation. CONCLUSION These results demonstrate for the first time the presence of P-Rex1 in platelets as well as its role in platelet secretion and aggregation induced by low-dose agonists for GPCR and by collagen.
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Affiliation(s)
- Feng Qian
- Department of Pharmacology, University of Illinois College of Medicine, 835 S Wolcott Ave, Chicago, IL 60612, USA
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