1
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Ballin M, Griep W, Patel M, Karl M, Mentrup T, Rivera‐Monroy J, Foo B, Schwappach B, Schröder B. The intramembrane proteases
SPPL2a
and
SPPL2b
regulate the homeostasis of selected
SNARE
proteins. FEBS J 2022; 290:2320-2337. [PMID: 36047592 DOI: 10.1111/febs.16610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/28/2022] [Accepted: 08/30/2022] [Indexed: 01/15/2023]
Abstract
Signal peptide peptidase (SPP) and SPP-like (SPPL) aspartyl intramembrane proteases are known to contribute to sequential processing of type II-oriented membrane proteins referred to as regulated intramembrane proteolysis. The ER-resident family members SPP and SPPL2c were shown to also cleave tail-anchored proteins, including selected SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins facilitating membrane fusion events. Here, we analysed whether the related SPPL2a and SPPL2b proteases, which localise to the endocytic or late secretory pathway, are also able to process SNARE proteins. Therefore, we screened 18 SNARE proteins for cleavage by SPPL2a and SPPL2b based on cellular co-expression assays, of which the proteins VAMP1, VAMP2, VAMP3 and VAMP4 were processed by SPPL2a/b demonstrating the capability of these two proteases to proteolyse tail-anchored proteins. Cleavage of the four SNARE proteins was scrutinised at the endogenous level upon SPPL2a/b inhibition in different cell lines as well as by analysing VAMP1-4 levels in tissues and primary cells of SPPL2a/b double-deficient (dKO) mice. Loss of SPPL2a/b activity resulted in an accumulation of VAMP1-4 in a cell type- and tissue-dependent manner, identifying these proteins as SPPL2a/b substrates validated in vivo. Therefore, we propose that SPPL2a/b control cellular levels of VAMP1-4 by initiating the degradation of these proteins, which might impact cellular trafficking.
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Affiliation(s)
- Moritz Ballin
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Wolfram Griep
- Biochemical Institute Christian Albrechts University Kiel Kiel Germany
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Mehul Patel
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Martin Karl
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Torben Mentrup
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
| | - Jhon Rivera‐Monroy
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Brian Foo
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Blanche Schwappach
- Department of Molecular Biology University Medical Center Göttingen Göttingen Germany
| | - Bernd Schröder
- Institute of Physiological Chemistry Technische Universität Dresden Dresden Germany
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2
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Fidler TP, Campbell RA, Funari T, Dunne N, Balderas Angeles E, Middleton EA, Chaudhuri D, Weyrich AS, Abel ED. Deletion of GLUT1 and GLUT3 Reveals Multiple Roles for Glucose Metabolism in Platelet and Megakaryocyte Function. Cell Rep 2018; 20:881-894. [PMID: 28746873 DOI: 10.1016/j.celrep.2017.06.083] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/08/2017] [Accepted: 06/27/2017] [Indexed: 01/08/2023] Open
Abstract
Anucleate platelets circulate in the blood to facilitate thrombosis and diverse immune functions. Platelet activation leading to clot formation correlates with increased glycogenolysis, glucose uptake, glucose oxidation, and lactic acid production. Simultaneous deletion of glucose transporter (GLUT) 1 and GLUT3 (double knockout [DKO]) specifically in platelets completely abolished glucose uptake. In DKO platelets, mitochondrial oxidative metabolism of non-glycolytic substrates, such as glutamate, increased. Thrombosis and platelet activation were decreased through impairment at multiple activation nodes, including Ca2+ signaling, degranulation, and integrin activation. DKO mice developed thrombocytopenia, secondary to impaired pro-platelet formation from megakaryocytes, and increased platelet clearance resulting from cytosolic calcium overload and calpain activation. Systemic treatment with oligomycin, inhibiting mitochondrial metabolism, induced rapid clearance of platelets, with circulating counts dropping to zero in DKO mice, but not wild-type mice, demonstrating an essential role for energy metabolism in platelet viability. Thus, substrate metabolism is essential for platelet production, activation, and survival.
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Affiliation(s)
- Trevor P Fidler
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA; Program in Molecular Medicine, University of Utah, Salt Lake City, UT 84112, USA; Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Robert A Campbell
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT 84112, USA; Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA
| | - Trevor Funari
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Nicholas Dunne
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Enrique Balderas Angeles
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Elizabeth A Middleton
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT 84112, USA; Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA
| | - Dipayan Chaudhuri
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Andrew S Weyrich
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT 84112, USA; Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA
| | - E Dale Abel
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT 84112, USA; Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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3
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Probing of primed and unprimed sites of calpains: Design, synthesis and evaluation of epoxysuccinyl-peptide derivatives as selective inhibitors. Eur J Med Chem 2014; 82:274-80. [DOI: 10.1016/j.ejmech.2014.05.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 05/19/2014] [Accepted: 05/23/2014] [Indexed: 11/20/2022]
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4
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Wu Z, Chen X, Liu F, Chen W, Wu P, Wieschhaus AJ, Chishti AH, Roche PA, Chen WM, Lin TJ. Calpain-1 contributes to IgE-mediated mast cell activation. THE JOURNAL OF IMMUNOLOGY 2014; 192:5130-9. [PMID: 24760147 DOI: 10.4049/jimmunol.1301677] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mast cells play a central role in allergy through secretion of both preformed and newly synthesized mediators. Mast cell mediator secretion is controlled by a complex network of signaling events. Despite intensive studies, signaling pathways in the regulation of mast cell mediator secretion remain incompletely defined. In this study, we examined the role of calpain in IgE-dependent mast cell activation. IgE-mediated activation of mouse bone marrow-derived mast cells enhanced calpain activity. Inhibition of calpain activity by a number of calpain inhibitors reduced IgE-mediated mast cell degranulation both in vitro and in vivo. Calpain inhibitors blocked IgE-mediated TNF and IL-6 production in vitro and reduced late-phase allergic response in vivo. Importantly, mouse calpain-1 null bone marrow-derived mast cells showed reduced IgE-mediated mast cell degranulation in vitro and in vivo, diminished cytokine and chemokine production in vitro, and impaired late-phase allergic response in vivo. Further studies revealed that calpain-1 deficiency led to specific attenuation of IκB-NF-κB pathway and IKK-SNAP23 pathway, whereas calcium flux, MAPK, Akt, and NFAT pathway proceed normally in IgE-activated calpain-1 null mast cells. Thus, calpain-1 is identified as a novel regulator in IgE-mediated mast cell activation and could serve as a potential therapeutic target for the management of allergic inflammation.
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Affiliation(s)
- Zhengli Wu
- Department of Microbiology and Immunology, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada
| | - Xiaochun Chen
- Department of Neurology, Affiliated Union Hospital of Fujian Medical University, Fuzhou, Fujian 350001, China
| | - Fang Liu
- Department of Microbiology and Immunology, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada
| | - Wei Chen
- College of Veterinary Medicine, Jilin University, Changchun, Jilin 130062, China
| | - Ping Wu
- Department of Microbiology and Immunology, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada
| | - Adam J Wieschhaus
- Department of Molecular Physiology and Pharmacology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111
| | - Athar H Chishti
- Department of Molecular Physiology and Pharmacology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111
| | - Paul A Roche
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Wei-Min Chen
- Department of Hematology, Fujian Provincial Hospital, Fuzhou, Fujian 350000, China
| | - Tong-Jun Lin
- Department of Microbiology and Immunology, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia B3K 6R8, Canada;
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5
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Kudryashova IV. Molecular mechanisms of short-term plasticity as a basis of frequency coding: The role of proteolytic systems. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414010097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Bánóczi Z, Tantos Á, Farkas A, Majer Z, Dókus LE, Tompa P, Hudecz F. New m-calpain substrate-based azapeptide inhibitors. J Pept Sci 2013; 19:370-6. [DOI: 10.1002/psc.2511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/05/2013] [Accepted: 03/05/2013] [Indexed: 01/12/2023]
Affiliation(s)
- Zoltán Bánóczi
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences; Eötvös Loránd University; Budapest Hungary
| | - Ágnes Tantos
- Institute of Enzymology, Biological Research Center; Hungarian Academy of Sciences; Budapest Hungary
| | - Attila Farkas
- Institute of Enzymology, Biological Research Center; Hungarian Academy of Sciences; Budapest Hungary
| | - Zsuzsa Majer
- Institute of Chemistry; Eötvös Loránd University; Budapest Hungary
| | - Levente E. Dókus
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences; Eötvös Loránd University; Budapest Hungary
| | - Péter Tompa
- Institute of Enzymology, Biological Research Center; Hungarian Academy of Sciences; Budapest Hungary
| | - Ferenc Hudecz
- Research Group of Peptide Chemistry, Hungarian Academy of Sciences; Eötvös Loránd University; Budapest Hungary
- Institute of Chemistry; Eötvös Loránd University; Budapest Hungary
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7
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Abstract
Platelet secretion plays a key role in thrombosis, thus the platelet secretory machinery offers a unique target to modulate hemostasis. We report the regulation of platelet secretion via phosphorylation of SNAP-23 at Ser95. Phosphorylation of this t-soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) occurs upon activation of known elements of the platelet signaling cascades (ie, phospholipase C, [Ca(2+)]i, protein kinase C) and requires IκB kinase (IKK)-β. Other elements of the nuclear factor κB/IκB cascade (ie, IKK-α,-β,-γ/NEMO and CARMA/MALT1/Bcl10 complex) are present in anucleate platelets and IκB is phosphorylated upon activation, suggesting that this pathway is active in platelets and implying a nongenomic role for IKK. Inhibition of IKK-β, either pharmacologically (with BMS-345541, BAY11-7082, or TPCA-1) or by genetic manipulation (platelet factor 4 Cre:IKK-β(flox/flox)), blocked SNAP-23 phosphorylation, platelet secretion, and SNARE complex formation; but, had no effect on platelet morphology or other metrics of platelet activation. Consistently, SNAP-23 phosphorylation enhanced membrane fusion of SNARE-containing proteoliposomes. In vivo studies with IKK inhibitors or platelet-specific IKK-β knockout mice showed that blocking IKK-β activity significantly prolonged tail bleeding times, suggesting that currently available IKK inhibitors may affect hemostasis.
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8
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Volpi E, Giusti L, Ciregia F, Da Valle Y, Giannaccini G, Berti S, Clerico A, Lucacchini A. Platelet proteome and clopidogrel response in patients with stable angina undergoing percutaneous coronary intervention. Clin Biochem 2012; 45:758-65. [DOI: 10.1016/j.clinbiochem.2012.03.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 01/27/2012] [Accepted: 03/23/2012] [Indexed: 12/20/2022]
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9
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Choi W, Karim ZA, Whiteheart SW. Protein expression in platelets from six species that differ in their open canalicular system. Platelets 2011; 21:167-75. [PMID: 20196629 DOI: 10.3109/09537101003611385] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Platelets contain an invaginated, tubular membranous structure called the surface-connected open canalicular system (SCCS or OCS), which is contiguous with the plasma membrane and serves as a site for granule fusion and as a reservoir of membrane for platelet spreading. According to ultrastructural studies, platelets from some species lack OCS. In an attempt to correlate biochemical and functional attributes with the presence of an OCS, platelets from human, mouse and dog (OCS(+)), and from cow, camel and horse (OCS(-)) were analysed for differential protein expression and aggregation in response to thrombin. Among the 18 different cytoskeletal and regulatory proteins examined, five (Rac1, RhoA, Ras, calmodulin and Src) were expressed at higher levels in OCS(+) platelets (p < 0.05). Given the role of Arf6 in the formation of tubular invaginations in nucleated cells, the levels of Arf6-GTP were analysed in OCS(+) and OCS(-) platelets. There was no significant correlation between the presence of OCS and total Arf6 or Arf6-GTP levels. Comparison of platelet aggregation between different species suggests that OCS(-) platelets have delayed responses. This comparison of platelets from six different species, which differ in their OCS, shows the differential expression of known signaling components and foreshadows future studies focusing on OCS formation and function.
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Affiliation(s)
- Wangsun Choi
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536-0509, USA
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10
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Dean WL. Role of platelet plasma membrane Ca 2+-ATPase in health and disease. World J Biol Chem 2010; 1:265-70. [PMID: 21537483 PMCID: PMC3083976 DOI: 10.4331/wjbc.v1.i9.265] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 08/24/2010] [Accepted: 08/31/2010] [Indexed: 02/05/2023] Open
Abstract
Platelets have essential roles in both health and disease. Normal platelet function is required for hemostasis. Inhibition of platelet function in disease or by pharmacological treatment results in bleeding disorders. On the other hand, hyperactive platelets lead to heart attack and stroke. Calcium is a major second messenger in platelet activation, and elevated intracellular calcium leads to hyperactive platelets. Elevated platelet calcium has been documented in hypertension and diabetes; both conditions increase the likelihood of heart attack and stroke. Thus, proper regulation of calcium metabolism in the platelet is extremely important. Plasma membrane Ca2+-ATPase (PMCA) is a major player in platelet calcium metabolism since it provides the only significant route for calcium efflux. In keeping with the important role of calcium in platelet function, PMCA is a highly regulated transporter. In human platelets, PMCA is activated by Ca2+/calmodulin, by cAMP-dependent phosphorylation and by calpain-dependent removal of the inhibitory peptide. It is inhibited by tyrosine phosphorylation and calpain-dependent proteolysis. In addition, the cellular location of PMCA is regulated by a PDZ-domain-dependent interaction with the cytoskeleton during platelet activation. Rapid regulation by phosphorylation results in changes in the rate of platelet activation, whereas calpain-dependent proteolysis and interaction with the cytoskeleton appears to regulate later events such as clot retraction. In hypertension and diabetes, PMCA expression is upregulated while activity is decreased, presumably due to tyrosine phosphorylation. Clearly, a more complete understanding of PMCA function in human platelets could result in the identification of new ways to control platelet function in disease states.
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Affiliation(s)
- William L Dean
- William L Dean, Department of Biochemistry and Molecular Biology, School of Medicine, University of Louisville, Louisville, KY 40292, United States
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11
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Inhibition of calpain but not caspase activity by spectrin fragments. Cell Mol Biol Lett 2010; 15:395-405. [PMID: 20467904 PMCID: PMC3074365 DOI: 10.2478/s11658-010-0015-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 04/25/2010] [Indexed: 11/29/2022] Open
Abstract
Calpains and caspases are ubiquitous cysteine proteases that are associated with a variety of cellular pathways. Calpains are involved in processes such as long term potentiation, cell motility and apoptosis, and have been shown to cleave non-erythroid (brain) α- and β-spectrin and erythroid β-spectrin. The cleavage of erythroid α-spectrin by calpain has not been reported. Caspases play an important role in the initiation and execution of apoptosis, and have been shown to cleave non-erythroid but not erythroid spectrin. We have studied the effect of spectrin fragments on calpain and caspase activities. The erythroid and non-erythroid spectrin fragments used were from the N-terminal region of α-spectrin, and C-terminal region of β-spectrin, both consisting of regions involved in spectrin tetramer formation. We observed that the all spectrin fragments exhibited a concentration-dependent inhibitory effect on calpain, but not caspase activity. It is clear that additional studies are warranted to determine the physiological significance of calpain inhibition by spectrin fragments. Our findings suggest that calpain activity is modulated by the presence of spectrin partial domains at the tetramerization site. It is not clear whether the inhibitory effect is substrate specific or is a general effect. Further studies of this inhibitory effect may lead to the identification and development of new therapeutic agents specifically for calpains, but not for caspases. Proteins/peptides with a coiled coil helical conformation should be studied for potential inhibitory effects on calpain activity.
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12
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Randriamboavonjy V, Fleming I. The Role of Calpain in Diabetes-Associated Platelet Hyperactivation. CARDIOVASCULAR PHARMACOLOGY - HEART AND CIRCULATION 2010; 59:235-57. [DOI: 10.1016/s1054-3589(10)59008-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Johnson JD, Otani K, Bell GI, Polonsky KS. Impaired insulin secretion in transgenic mice over-expressing calpastatin in pancreatic β-cells. Islets 2009; 1:242-8. [PMID: 21099278 PMCID: PMC3044710 DOI: 10.4161/isl.1.3.9780] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Calpains are a family of calcium-activated proteases involved in a number of cellular functions including cell death, proliferation and exocytosis. The finding that variation in the calpain-10 gene increases type 2 diabetes risk in some populations has increased interest in determining the potential role of calpains in pancreatic β-cell function. In the present study, transgenic mice (Cast (RIP)) expressing an endogenous calpain inhibitor, calpastatin, in pancreatic β-cells were used to dissect the role of the calpain system in the regulation insulin secretion in vivo and in vitro. Glucose concentrations after the administration of intraperitoneal glucose were significantly increased in Cast (RIP) mice compared with wildtype littermate controls. This was associated with a reduction in glucose-stimulated insulin secretion in vivo. Using pancreas perfusion, static islet incubation and islet perifusion, it was demonstrated that Cast (RIP) islets hypersecreted insulin at low glucose, but exhibited significantly impaired insulin responses to high glucose. Examination of insulin release and calcium signals from isolated islets indicated that distal components of the insulin exocytotic pathway were abnormal in Cast (RIP) mice. Cast (RIP) islets had modestly reduced expression of Rab3a and other critical components in the late steps of insulin exocytosis. These studies provide the first evidence that blocking endogenous calpain activity partially impairs insulin release in vivo and in vitro by targeting distal components of the insulin exocytotic machinery.
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Affiliation(s)
- James D. Johnson
- Department of Cellular and Physiological Sciences; Department of Surgery; University of British Columbia; Vancouver, Canada
- Correspondence to: James D. Johnson and Kenneth S. Polonsky
| | - Kenichi Otani
- Department of Internal Medicine; Washington University; St. Louis; MO USA
| | - Graeme I. Bell
- Departments of Medicine and Human Genetics; The University of Chicago; Chicago; IL USA
| | - Kenneth S. Polonsky
- Department of Internal Medicine; Washington University; St. Louis; MO USA
- Correspondence to: James D. Johnson and Kenneth S. Polonsky
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14
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Khoutorsky A, Spira ME. Activity-dependent calpain activation plays a critical role in synaptic facilitation and post-tetanic potentiation. Learn Mem 2009; 16:129-41. [DOI: 10.1101/lm.1275709] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Grumelli C, Berghuis P, Pozzi D, Caleo M, Antonucci F, Bonanno G, Carmignoto G, Dobszay MB, Harkany T, Matteoli M, Verderio C. Calpain activity contributes to the control of SNAP-25 levels in neurons. Mol Cell Neurosci 2008; 39:314-23. [PMID: 18721885 DOI: 10.1016/j.mcn.2008.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 07/04/2008] [Accepted: 07/08/2008] [Indexed: 01/20/2023] Open
Abstract
Calpains are a family of calcium-dependent proteases with abundant expression in the CNS, and potent in cleaving some synaptic components. Assessment of calpain activity by its fluorescent substrate, Boc-Leu-Met-CMAC, revealed that cultured neurons display a significant level of constitutive enzyme activity. Notably, calpain activity differs in distinct neuronal populations, with a significantly higher level of activity in GABAergic cells. Using selectively-enriched cultures of fast-spiking GABAergic interneurons, we show that calpain activity partially contributes to the post-translational down regulation of SNAP-25, a calpain substrate, in differentiated GABA cells. In addition, we demonstrate that SNAP-25 is cleaved by calpain in response to acute seizures induced by intraperitoneal kainate injection in vivo. These data indicate that calpains in neurons are active even at physiological calcium concentrations and that different levels of calpain activation in selected neuron subtypes may contribute to the pattern of synaptic protein expression.
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Affiliation(s)
- Carlotta Grumelli
- Dipartimento di Farmacologia Medica, Istituto CNR di Neuroscienze, Universita' di Milano, Italy
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16
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Bánóczi Z, Alexa A, Farkas A, Friedrich P, Hudecz F. Novel Cell-Penetrating Calpain Substrate. Bioconjug Chem 2008; 19:1375-81. [DOI: 10.1021/bc800021y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Zoltán Bánóczi
- Research Group of Peptide Chemistry, Eötvös L. University, Hungarian Academy of Sciences, P.O. Box 32, 1518 Budapest, 112 Hungary, Institute of Enzymology, Biological Research Center, Hungarian Academy of Science, P.O. Box 7, 1518 Budapest, Hungary, and Department of Organic Chemistry, Eötvös L. University, Pázmány P. S 1/A, H-1117 Budapest, Hungary
| | - Anita Alexa
- Research Group of Peptide Chemistry, Eötvös L. University, Hungarian Academy of Sciences, P.O. Box 32, 1518 Budapest, 112 Hungary, Institute of Enzymology, Biological Research Center, Hungarian Academy of Science, P.O. Box 7, 1518 Budapest, Hungary, and Department of Organic Chemistry, Eötvös L. University, Pázmány P. S 1/A, H-1117 Budapest, Hungary
| | - Attila Farkas
- Research Group of Peptide Chemistry, Eötvös L. University, Hungarian Academy of Sciences, P.O. Box 32, 1518 Budapest, 112 Hungary, Institute of Enzymology, Biological Research Center, Hungarian Academy of Science, P.O. Box 7, 1518 Budapest, Hungary, and Department of Organic Chemistry, Eötvös L. University, Pázmány P. S 1/A, H-1117 Budapest, Hungary
| | - Péter Friedrich
- Research Group of Peptide Chemistry, Eötvös L. University, Hungarian Academy of Sciences, P.O. Box 32, 1518 Budapest, 112 Hungary, Institute of Enzymology, Biological Research Center, Hungarian Academy of Science, P.O. Box 7, 1518 Budapest, Hungary, and Department of Organic Chemistry, Eötvös L. University, Pázmány P. S 1/A, H-1117 Budapest, Hungary
| | - Ferenc Hudecz
- Research Group of Peptide Chemistry, Eötvös L. University, Hungarian Academy of Sciences, P.O. Box 32, 1518 Budapest, 112 Hungary, Institute of Enzymology, Biological Research Center, Hungarian Academy of Science, P.O. Box 7, 1518 Budapest, Hungary, and Department of Organic Chemistry, Eötvös L. University, Pázmány P. S 1/A, H-1117 Budapest, Hungary
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17
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Synthetic calpain activator boosts neuronal excitability without extra Ca2+. Mol Cell Neurosci 2008; 38:629-36. [PMID: 18599308 DOI: 10.1016/j.mcn.2008.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 05/09/2008] [Accepted: 05/15/2008] [Indexed: 02/06/2023] Open
Abstract
Earlier we have shown that an equimolar mixture of calpastatin subdomains A and C (19 amino acids each) strongly activates m-calpain in vitro. In the present work we developed a membrane-permeable activator system, by conjugating an oligo-arginine tail to both peptides. We tested calpain activation as well as synaptic excitability on rat brain slices ex vivo. In hippocampal slices both basic excitability and long-term synaptic efficacy were significantly increased upon treatment with the activator. We propose that the activator peptide conjugates can be used with any mammalian cell, to specifically challenge the calpain system apparently without raising cytoplasmic Ca2+. Such an effector may be a useful tool in dissecting intracellular mechanisms involving the calpain system.
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18
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Badol P, David-Dufilho M, Auger J, Whiteheart SW, Rendu F. Thiosulfinates modulate platelet activation by reaction with surface free sulfhydryls and internal thiol-containing proteins. Platelets 2008; 18:481-90. [PMID: 17852771 DOI: 10.1080/09537100701271828] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Thiosulfinates are characteristic flavors of Allium vegetables, with a highly reactive S-S=O group, that we previously showed to inhibit platelet aggregation through calpain-dependent mechanisms. With the aim to clarify the mode of action of these redox phytochemicals, we studied their effect on extracellular free sulfhydryls in relation to their effect on platelet responses (Ca2+ signals, release reaction, and aIIb3 integrin activation state). At the platelet surface, thiosulfinate dose-dependently increased the basal level of free sulfhydryls, independently of protein disulfide isomerase activity. This generation of new free sulfhydryls was associated with: (i) a three fold increase in labeling of resting platelets with an anti ligand-induced binding site antibody and (ii) marked inhibition of subsequent aIIb3 activation by agonists. Thiosulfinates increased the basal intracellular Ca2+ level of platelets. In activated platelets, they markedly inhibited the Ca2+ mobilization independently of the external Ca2+, the calpain-induced SNAP-23 cleavage and the granule release. In platelet free systems, thiosulfinates inhibited the activity of purified calpain and the free sulfhydryl of glutathione without any reducing properties on disulfides. The results demonstrate for the first time that thiosulfinates rapidly interact with sulfhydryls both at the platelet surface and inside the cell on intracellular cysteine-proteins, especially calpain. Inhibition of free cysteine and glutathione in whole blood may also contribute to their anti-aggregant properties. Such sulfur compounds are of interest for the development of a new class of antithrombotic agents.
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Affiliation(s)
- Perrine Badol
- Université Pierre et Marie Curie-Paris 6, Paris, France
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19
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Abstract
The plasma membrane Ca(2+)-ATPase (PMCA) plays an essential role in maintaining low cytosolic Ca(2+) in resting human platelets by extruding Ca(2+) from the cytoplasm across the plasma membrane. Since PMCA is the main agent of Ca(2+) efflux in platelets, it is a key point for regulation of platelet Ca(2+) metabolism. PMCA has been shown to be an excellent substrate for the Ca(2+)-activated cysteine protease calpain, a major platelet protein that is turned on during platelet activation. The objectives of the present work were to determine if PMCA is degraded during thrombin- and collagen-mediated platelet activation, and if calpain is responsible. The kinetics of PMCA degradation during platelet activation were analysed using SDS polyacrylamide gel electrophoresis and immunoblotting. The role of calpain was tested using the calpain inhibitors calpeptin and ALLN. Platelet activation mediated by both collagen and thrombin resulted in degradation of 60% of platelet PMCA within 18 minutes. Calpeptin and ALLN significantly inhibited the rate and extent of PMCA degradation. We conclude that calpain-mediated degradation of PMCA during platelet activation likely contributes significantly to Ca(2+) regulation and, therefore, to platelet function.
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Affiliation(s)
- Charles S Brown
- Department of Biochemistry & Molecular Biology, University of Louisille School of Medicine, Louisville, KY 40292, USA
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20
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Turner MD. Coordinated control of both insulin secretion and insulin action through calpain-10-mediated regulation of exocytosis? Mol Genet Metab 2007; 91:305-7. [PMID: 17560157 DOI: 10.1016/j.ymgme.2007.04.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 04/27/2007] [Indexed: 12/31/2022]
Abstract
Calpain-10 was first identified through a genome scan seeking to identify diabetes predisposition genes. Both genetic and functional data has since indicated that calpain-10 has an important role in insulin resistance and intermediate phenotypes, including those associated with adipocytes and skeletal muscle. Evidence presented in this issue by Brown, Yeaman, and Walker utilizes siRNA technology to specifically knock down calpain-10 expression, and suggests that calpain-10 facilitates GLUT4 translocation through effects on the distal secretory pathway. Calpain-10 is also an important molecule in the pancreatic beta-cell, where it has been shown to regulate exocytosis through partial proteolysis of a member of the secretory granule fusion machinery. In addition, calpain-10 has also been implicated in reorganization of the actin cytoskeleton that accompanies both GLUT4 vesicle translocation and insulin secretion. Taken together, these findings provide fresh hope for the development of novel diabetic treatments, utilizing either pharmacological activators that specifically target calpain-10, or through targeted calpain-10 gene therapy. Therapeutic intervention in this way could simultaneously enhance both insulin secretion and insulin action.
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Affiliation(s)
- Mark D Turner
- Centre for Diabetes and Metabolic Medicine, Institute of Cell and Molecular Science, Barts and The London Queen Mary's School of Medicine and Dentistry, University of London, London E1 2AT, United Kingdom.
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21
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Evans JS, Turner MD. Emerging functions of the calpain superfamily of cysteine proteases in neuroendocrine secretory pathways. J Neurochem 2007; 103:849-59. [PMID: 17666040 DOI: 10.1111/j.1471-4159.2007.04815.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The first calpain protease was discovered over 40 years ago now, yet despite the vast amount of literature that has subsequently emerged detailing their involvement in the pathophysiology of a variety of human diseases, it is only in the last decade that calpain-mediated actions along the secretory pathway have begun to emerge. However, the number of secretory pathway substrates identified and their diversity of function continues to grow. This review summarizes our current knowledge of calpain-mediated mechanisms of action that are pertinent to synaptic vesicle assembly and budding, cytoskeletal organization, endosomal recycling, and exocytotic membrane fusion.
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Affiliation(s)
- Joanne S Evans
- Centre for Diabetes and Metabolic Medicine, Institute of Cell and Molecular Science, London, UK
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22
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Abstract
PURPOSE OF REVIEW There is considerable interest in understanding the function and mechanism of calpains in platelet aggregation, spreading, and granular secretion pathways. Recent insights from the calpain-1 knockout platelets suggest a pivotal role of these cysteine proteases in the regulation of outside-in signaling, aggregation, and clot retraction. RECENT FINDINGS The calpain-1 knockout mouse provided direct evidence for the role of calpain-1 in platelet aggregation and clot retraction. Reduced tyrosine phosphorylation of platelet proteins correlated with reduced platelet aggregation and clot retraction. Future investigations of the mechanism of platelet defects in calpain-1 null mice may unveil the physiological functions of this important and elusive protease in mammalian cells. SUMMARY This review focuses on the role of calpains in platelets with a particular emphasis on recent findings in calpain-1 null platelets. Previous studies used synthetic inhibitors to study the role of calpains in platelet function yielding useful information about the identification of calpain substrates. The development of calpain-1 null mice demonstrated that calpain-1 plays an important function in the regulation of platelet aggregation and clot retraction. Since the combined deletion of calpain-1 and calpain-2 genes results in embryonic lethality, the calpain-1 null mouse remains the only experimental model available to study the physiological role of calpains in mammalian cells.
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Affiliation(s)
- Shafi M Kuchay
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL 60612, USA
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23
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Banóczi Z, Tantos A, Farkas A, Tompa P, Friedrich P, Hudecz F. Synthesis of cell-penetrating conjugates of calpain activator peptides. Bioconjug Chem 2007; 18:130-7. [PMID: 17226965 DOI: 10.1021/bc0601976] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Calpains, the intracellular proteolytic enzymes, play important roles in various processes in cells. The lack of calpain or its overexpression is thought to be an underlying factor in some diseases. In this study, we report the synthesis of a new group of cell-penetrating calpastatin-peptide conjugates with the activating capacity of m-calpain intracellularly. In these constructs, peptides related to the calpastatin A or C subunit with the capabiliy of activation of isolated m-calpain was covalently conjugated to the C-terminal of penetratin via amide, thioether, or disulfide bond. These conjugates were prepared by solid-phase synthesis and/or by chemical ligation and properly characterized (MS, HPLC). Our results using isolated m-calpain suggest that conjugation does not interfere with the enzyme-activating effect of the calpastatin peptides; in fact, the efficiency of the conjugates was markedly higher. The conjugates with different bonds showed essentially the same level of activation. Internalization experiments with fluorophore (4-[7-hydroxycoumaryl] acetic acid (Hca) at the N-terminal of penetratin and/or 5(6)-carboxyfluorescein (cf)) labeled conjugates show that these constructs are taken up by COS-7 cells. Using cell lysates produced after incubation with the 1:1 (mol/mol) mixture of calpastatin A and C peptide conjugates, we found a significant calpain activating effect. We also noticed that the conjugate even with a disulfide bond between the components seems to be stable and activate m-calpain after intracellular translocation under the conditions studied. To the best of our knowledge, this is the first report to describe conjugates with an m-calpain activating effect on isolated enzymes and more importantly within living cells after transmembrane delivery. Thus, these conjugates seem to be appropriate as molecular tools to activate intracellular m-calpain and to study calpain functions in living cells.
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Affiliation(s)
- Zoltan Banóczi
- Research Group of Peptide Chemistry, Eötvös L. University, Hungarian Academy of Sciences, P.O. Box 32, 1518 Budapest 112 Hungary
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24
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Gupta R, Chakrabarti P, Dikshit M, Dash D. Late signaling in the activated platelets upregulates tyrosine phosphatase SHP1 and impairs platelet adhesive functions: Regulation by calcium and Src kinase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:131-40. [PMID: 17046078 DOI: 10.1016/j.bbamcr.2006.08.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 08/28/2006] [Accepted: 08/30/2006] [Indexed: 10/24/2022]
Abstract
Sustained stimulation of platelets with protease-activated receptor agonists in presence of extracellular calcium was associated with tyrosine dephosphorylation of specific proteins of relative mobilities 35, 67, and 75 kDa. From phosphatase assays and inhibitor studies SHP1, a Src homology 2 (SH2) domain-containing tyrosine phosphatase expressed abundantly in hemopoietic cells, was found to be upregulated in platelets between 25 and 30 min following thrombin stimulation. Concomitantly, SHP1 was tyrosine phosphorylated by, and coprecipitated with, Src tyrosine kinase. SHP1 activation, association with Src and dephosphorylation of specific proteins were dependent on extracellular calcium and maintenance of a higher cytosolic calcium plateau. There was progressive impairment of platelet functions like aggregability and clot retraction, associated with downregulation of fibrinogen-binding affinity of integrin alpha(IIb)beta(3), in the platelets exposed to thrombin for 45 min. This could reflect the late physiological changes in platelets when the cells are consistently exposed to stimulatory signals under thrombogenic environment in vivo.
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Affiliation(s)
- Ramkrishna Gupta
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, India
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25
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Ramos IB, Miranda K, de Souza W, Oliveira DMP, Lima APCA, Sorgine MHF, Machado EA. Calcium-regulated fusion of yolk granules is important for yolk degradation during early embryogenesis of Rhodnius prolixusStahl. J Exp Biol 2007; 210:138-48. [PMID: 17170157 DOI: 10.1242/jeb.02652] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
SUMMARY
This study examined the process of membrane fusion of yolk granules (YGs)during early embryogenesis of Rhodnius prolixus. We show that eggs collected at days 0 and 3 after oviposition contain different populations of YGs, for example day-3 eggs are enriched in large YGs (LYGs). Day-3 eggs also contain the highest free [Ca2+] during early embryogenesis of this insect. In vitro incubations of day-0 YGs with [Ca2+]similar to those found in day-3 eggs resulted in the formation of LYGs, as observed in vivo. Fractionation of LYGs and small YGs (SYGs) and their subsequent incubation with the fluorescent membrane marker PKH67 showed a calcium-dependent transference of fluorescence from SYGs to LYGs, possibly as the result of membrane fusion. Acid phosphatase and H+-PPase activities were remarkably increased in day-3 LYGs and in calcium-treated day-0 LYGs. Both fractions were found to contain vitellins as major components, and incubation of YGs with calcium induced yolk proteolysis in vitro. Altogether, our results suggest that calcium-induced membrane fusion events take part in yolk degradation, leading to the assembly of the yolk mobilization machinery.
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Affiliation(s)
- I B Ramos
- Laboratório de Entomologia Médica, Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro (UFRJ), Cidade Universitária--Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brasil
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26
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Ramos IB, Miranda K, De Souza W, Machado EA. Calcium-regulated fusion of yolk granules during early embryogenesis ofPeriplaneta americana. Mol Reprod Dev 2006; 73:1247-54. [PMID: 16868923 DOI: 10.1002/mrd.20560] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This work reported membrane fusion of yolk granules (YGs) during early embryogenesis of the insect Periplaneta americana (P. americana). We showed that eggs from Day 5 of embryogenesis possess a greater amount of enlarged YGs in comparison with Day 1. Day 5 is also the period when the largest amount of free calcium is found (approximately 17 mM) within the oothecae from early embryogenesis. Treatment of Day 1-YGs fraction with 17 mM Ca2+ resulted in a YG size pattern very similar to the one observed in Day 5 eggs, where enlarged YGs were formed. YG membrane fusion was observed by fluorescent membrane dye transfer from previously labeled small YGs to larger ones and was also visualized by electron microscopy. We also showed that the small "in fusion" YGs seemed to be acidic, suggesting that acidification is correlated with YG membrane fusion. Hence, it was shown that YGs are capable of membrane fusion in a calcium-dependent manner and this process probably occurs in vivo during early embryogenesis of P. americana.
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Affiliation(s)
- I B Ramos
- Laboratório de Entomologia Médica do Programa de Parasitologia e Biologia Celular, Instituto de Biofísica Carlos Chagas Filho (IBCCF), Brasil
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27
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Choi W, Karim ZA, Whiteheart SW. Arf6 plays an early role in platelet activation by collagen and convulxin. Blood 2005; 107:3145-52. [PMID: 16352809 PMCID: PMC1895749 DOI: 10.1182/blood-2005-09-3563] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Small GTPases play critical roles in hemostasis, though the roster of such molecules in platelets is not complete. In this study, we report the presence of Ras-related GTPases of the ADP-ribosylation factor (Arf) family. Platelets contain Arf1 or 3 and Arf6, with the latter being predominantly membrane associated. Using effector domain pull-down assays, we show, counter to other GTPases, that Arf6-GTP is present in resting platelets and decreases rapidly upon activation with collagen or convulxin. This decrease does not completely rely on secondary agonists (ADP and thromboxane A2) or require integrin signaling. The decrease in free Arf6-GTP temporally precedes activation of Rho family GTPases (RhoA, Cdc42, and Rac1). Using a membrane-permeant, myristoylated peptide, which mimics the N-terminus of Arf6, we show that the Arf6-GTP decrease is essential for collagen- and convulxin-induced aggregation, platelet adherence, and spreading on collagen-coated glass. Treatment with this peptide also affects the activation of Rho family GTPases, but has little effect on RalA and Rap1 or on agonist-induced calcium mobilization. These data show that Arf6 is a key element in activation through GPVI, and is required for activation of the Rho family GTPases and the subsequent cytoskeletal rearrangements needed for full platelet function.
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Affiliation(s)
- Wangsun Choi
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536-0509, USA
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28
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Garcia M, Bondada V, Geddes JW. Mitochondrial localization of mu-calpain. Biochem Biophys Res Commun 2005; 338:1241-7. [PMID: 16259951 DOI: 10.1016/j.bbrc.2005.10.081] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 10/14/2005] [Indexed: 11/19/2022]
Abstract
Calcium-dependent cysteine proteases, calpains, have physiological roles in cell motility and differentiation but also play a pathological role following insult or disease. The ubiquitous calpains are widely considered to be cytosolic enzymes, although there has been speculation of a mitochondrial calpain. Within a highly enriched fraction of mitochondria obtained from rat cortex and SH-SY5Y human neuroblastoma cells, immunoblotting demonstrated enrichment of the 80kDa mu-calpain large subunit and 28kDa small subunit. In rat cortex, antibodies against domains II and III of the large mu-calpain subunit also detected a 40kDa fragment, similar to the autolytic fragment generated following incubation of human erythrocyte mu-calpain with Ca(2+). Mitochondrial proteins including apoptosis inducing factor and mitochondrial Bax are calpain substrates, but the mechanism by which calpains gain access to these proteins is uncertain. Mitochondrial localization of mu-calpain places the enzyme in proximity to its mitochondrial substrates and to Ca(2+) released from mitochondrial stores.
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Affiliation(s)
- Matthew Garcia
- Spinal Cord and Brain Injury Research Center and Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA
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29
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Ando K, Kudo Y, Takahashi M. Negative regulation of neurotransmitter release by calpain: a possible involvement of specific SNAP-25 cleavage. J Neurochem 2005; 94:651-8. [PMID: 15992386 DOI: 10.1111/j.1471-4159.2005.03160.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Synaptic transmission is conducted by neurotransmitters released from presynaptic nerve terminals by means of Ca2+-dependent exocytosis of synaptic vesicles. Formation of a complex of soluble N-ethylmaleimide-sensitive fusion protein receptor (SNARE) proteins, including vesicle-associated membrane protein-2 (VAMP-2) in the synaptic vesicle membrane, and syntaxin 1 and synaptosomal-associated protein of 25 kDa (SNAP-25) in the plasma membrane, is essential for exocytosis. Ionomycin treatment of cultured rat cerebellar granule cells led to cleavage of SNAP-25, but not syntaxin 1 and VAMP-2, that was dependent on extracellular Ca2+. Cleavage was also induced by N-methyl-D-aspartate (NMDA) treatment, but not by depolarization. The use of various site-specific antibodies to SNAP-25, suggested that the cleavage site was in the N-terminal domain of SNAP-25. Calpain inhibitors abolished the Ca2+-dependent cleavage of SNAP-25 and markedly facilitated Ca2+-dependent glutamate (Glu) release from cerebellar granule cells. These results suggest that calpain may play an important role in the long-lasting regulation of synaptic transmission by suppressing neurotransmitter release, possibly through the proteolytic cleavage of SNAP-25.
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Affiliation(s)
- Kosuke Ando
- School of Life Sciences, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo, Japan
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30
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Marshall C, Hitman GA, Partridge CJ, Clark A, Ma H, Shearer TR, Turner MD. Evidence that an isoform of calpain-10 is a regulator of exocytosis in pancreatic beta-cells. Mol Endocrinol 2004; 19:213-24. [PMID: 15471947 DOI: 10.1210/me.2004-0064] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Calpain-10 (CAPN10) is the first type 2 diabetes susceptibility gene to be identified through a genome scan, with polymorphisms being associated with altered CAPN10 expression. Functional data have been hitherto elusive, but we report here a corresponding increase between CAPN10 expression level and regulated insulin secretion. Pancreatic beta-cell secretory granule exocytosis is mediated by the soluble N-ethylmaleimide-sensitive fusion protein attachment receptor protein complex of synaptosomal-associated protein of 25 kDa (SNAP-25), syntaxin 1, and vesicle-associated membrane protein 2. We report, for the first time, direct binding of a calpain-10 isoform with members of this complex. Furthermore, SNAP-25 undergoes a Ca2+-dependent partial proteolysis during exocytosis, with calpain protease inhibitor similarly suppressing both insulin secretion and SNAP-25 proteolysis. Based upon these findings, we postulate that an isoform of calpain-10 is a Ca2+-sensor that functions to trigger exocytosis in pancreatic beta-cells.
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Affiliation(s)
- Catriona Marshall
- Centre for Diabetes and Metabolic Medicine, Institute of Cell and Molecular Science, Barts and The London, Queen Mary's School of Medicine and Dentistry, University of London, Whitechapel, London E1 1BB, United Kingdom
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31
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Raynaud F, Bonnal C, Fernandez E, Bremaud L, Cerutti M, Lebart MC, Roustan C, Ouali A, Benyamin Y. The calpain 1-alpha-actinin interaction. Resting complex between the calcium-dependent protease and its target in cytoskeleton. ACTA ACUST UNITED AC 2004; 270:4662-70. [PMID: 14622253 DOI: 10.1046/j.1432-1033.2003.03859.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Calpain 1 behaviour toward cytoskeletal targets was investigated using two alpha-actinin isoforms from smooth and skeletal muscles. These two isoforms which are, respectively, sensitive and resistant to calpain cleavage, interact with the protease when using in vitro binding assays. The stability of the complexes in EGTA [Kd(-Ca2+) = 0.5 +/- 0.1 microM] was improved in the presence of 1 mm calcium ions [Kd(+Ca2+) = 0.05 +/- 0.01 microM]. Location of the binding structures shows that the C-terminal domain of alpha-actinin and each calpain subunit, 28 and 80 kDa, participates in the interaction. In particular, the autolysed calpain form (76/18) affords a similar binding compared to the 80/28 intact enzyme, with an identified binding site in the catalytic subunit, located in the C-terminal region of the chain (domain III-IV). The in vivo colocalization of calpain 1 and alpha-actinin was shown to be likely in the presence of calcium, when permeabilized muscle fibres were supplemented by exogenous calpain 1 and the presence of calpain 1 in Z-line cores was shown by gold-labelled antibodies. The demonstration of such a colocalization was brought by coimmunoprecipitation experiments of calpain 1 and alpha-actinin from C2.7 myogenic cells. We propose that calpain 1 interacts in a resting state with cytoskeletal targets, and that this binding is strengthened in pathological conditions, such as ischaemia and dystrophies, associated with high calcium concentrations.
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Affiliation(s)
- Fabrice Raynaud
- UMR 5539 - CNRS, laboratoire de Motilité Cellulaire - EPHE, cc107, USTL, Montpellier, France
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32
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Schraw TD, Rutledge TW, Crawford GL, Bernstein AM, Kalen AL, Pessin JE, Whiteheart SW. Granule stores from cellubrevin/VAMP-3 null mouse platelets exhibit normal stimulus-induced release. Blood 2003; 102:1716-22. [PMID: 12738662 DOI: 10.1182/blood-2003-01-0331] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It is widely accepted that the platelet release reaction is mediated by heterotrimeric complexes of integral membrane proteins known as SNAREs (SNAP receptors). In an effort to define the precise molecular machinery required for platelet exocytosis, we have analyzed platelets from cellubrevin/VAMP-3 knockout mice. Cellubrevin/VAMP-3 has been proposed to be a critical v-SNARE for human platelet exocytosis; however, data reported here suggest that it is not required for platelet function. Upon stimulation with increasing concentrations of thrombin, collagen, or with thrombin for increasing time there were no differences in secretion of [3H]-5HT (dense core granules), platelet factor IV (alpha granules), or hexosaminidase (lysosomes) between null and wild-type platelets. There were no gross differences in bleeding times nor in agonist-induced aggregation measured in platelet-rich plasma or with washed platelets. Western blotting of wild-type, heterozygous, and null platelets confirmed the lack of cellubrevin/VAMP-3 in nulls and showed that most elements of the secretion machinery are expressed at similar levels. While the secretory machinery in mice was similar to humans, mice did express apparently higher levels of synaptobrevin/VAMP-2. These data show that the v-SNARE, cellubrevin/VAMP-3 is not a requirement for the platelet release reaction in mice.
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Affiliation(s)
- Todd D Schraw
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, 800 Rose St, Lexington, KY 40536, USA.
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33
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Schraw TD, Lemons PP, Dean WL, Whiteheart SW. A role for Sec1/Munc18 proteins in platelet exocytosis. Biochem J 2003; 374:207-17. [PMID: 12773094 PMCID: PMC1223584 DOI: 10.1042/bj20030610] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2003] [Revised: 05/27/2003] [Accepted: 05/29/2003] [Indexed: 11/17/2022]
Abstract
A critical aspect of haemostasis is the release of clot-forming components from the three intra-platelet stores: dense-core granules, alpha granules and lysosomes. Exocytosis from these granules is mediated by soluble proteins [N-ethylmaleimide-sensitive fusion protein (NSF) and soluble NSF attachment proteins (SNAPs)] and integral membrane proteins [vesicle and target SNAP receptors (v- and t-SNAREs)]. Three Sec1/Munc18 proteins (SM proteins) are present in platelets (Munc18a, Munc18b and Munc18c) and they bind to and potentially regulate specific syntaxin t-SNAREs. In resting platelets, these SM proteins associate with granules and open canalicular system membranes predominantly but not with the plasma membrane. Munc18a binds to syntaxin 2 alone and does not associate with other members of the core SNARE complex. Munc18b associates with a larger complex that contains synaptosome-associated protein of 23 kDa (SNAP-23) and cellubrevin/vesicle-associated membrane protein 3. Munc18c associates with both syntaxins 2 and 4, with synaptosome-associated protein of 23 kDa (SNAP-23) and with a v-SNARE. On stimulation, most of the platelet SM proteins are still found in membrane fractions. Phosphorylation of each Munc18 increases in thrombin-treated cells and phosphorylated Munc18c remains associated with syntaxins 2 and 4, but its affinity for the SNAREs appears to be reduced. To determine the functional role of the platelet SM proteins, we examined the effects of Munc18-based peptides (Munc18a peptide 3 and Munc18c peptide 3). Addition of the peptides to permeabilized platelets inhibits secretion from all three platelet granules. These peptides also inhibit agonist-induced aggregation in saponin-permeabilized platelets. These studies demonstrate a clear role for SM proteins in platelet exocytosis and aggregation and suggest a dominant role for Munc18c in all three granule-release events.
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Affiliation(s)
- Todd D Schraw
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, 800 Rose Street, Lexington, KY 40536, USA
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34
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Abstract
The energy-dependent release of granule contents from activated platelets is a well-established component of normal hemostasis and thrombosis. A role for membrane fusion in this process has been presumed for decades, but only recently have the mechanisms of platelet membrane fusion been investigated at the molecular level. Such studies have demonstrated that platelet membrane fusion is controlled by lipid components of the membrane bilayer, by transmembrane proteins termed SNARE proteins, and by chaperone proteins that interact with SNARE proteins. This core membrane fusion machinery is controlled by activation-dependent changes in cytoskeletal organization, intracellular calcium levels, kinase activity, and intracellular protease activity. Through these mechanisms, interactions of ligands with their cognate cell-surface receptors are transmitted to the membrane fusion machinery to facilitate membrane fusion and secretion of granule contents from platelets.
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Affiliation(s)
- Robert Flaumenhaft
- Center for Hemostasis and Thrombosis Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass 02115, USA.
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