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Targeted gene inactivation reveals a functional role of calpain-1 in platelet spreading.

ABSTRACT: Calpains are implicated in a wide range of cellular functions including the maintenance of hemostasis via the regulation of cytoskeletal modifications in platelets.Determine the functional role of calpain isoforms in platelet spreading.Platelets from calpain-1(-/-) mice show enhanced spreading on collagen- and fibrinogen-coated surfaces as revealed by immunofluorescence, differential interference contrast (DIC) and scanning electron microscopy. The treatment of mouse platelets with MDL, a cell permeable inhibitor of calpains 1/2, resulted in increased spreading. The PTP1B-mediated enhanced tyrosine dephosphorylation in calpain-1(-/-) platelets did not fully account for the enhanced spreading as platelets from the double knockout mice lacking calpain-1 and PTP1B showed only a partial rescue of the spreading phenotype. In non-adherent platelets, proteolysis and GTPase activity of RhoA and Rac1 were indistinguishable between the wild-type (WT) and calpain-1(-/-) platelets. In contrast, the ECM-adherent calpain-1(-/-) platelets showed higher Rac1 activity at the beginning of spreading, whereas RhoA was more active at later time points. The ECM-adherent calpain-1(-/-) platelets showed an elevated level of RhoA protein but not Rac1 and Cdc42. Proteolysis of recombinant RhoA, but not Rac1 and Cdc42, indicates that RhoA is a calpain-1 substrate in vitro.Potentiation of the platelet spreading phenotype in calpain-1(-/-) mice suggests a novel role of calpain-1 in hemostasis, and may explain the normal bleeding time observed in the calpain-1(-/-) mice.

SUBMITTER: Kuchay SM

PROVIDER: S-EPMC3956748 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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Targeted gene inactivation reveals a functional role of calpain-1 in platelet spreading.

Kuchay S M SM Wieschhaus A J AJ Marinkovic M M Herman I M IM Chishti A H AH

Journal of thrombosis and haemostasis : JTH 20120601 6

<h4>Background</h4>Calpains are implicated in a wide range of cellular functions including the maintenance of hemostasis via the regulation of cytoskeletal modifications in platelets.<h4>Objectives</h4>Determine the functional role of calpain isoforms in platelet spreading.<h4>Methods and results</h4>Platelets from calpain-1(-/-) mice show enhanced spreading on collagen- and fibrinogen-coated surfaces as revealed by immunofluorescence, differential interference contrast (DIC) and scanning electr ...[more]

PMID: 22458296

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Targeted gene inactivation reveals a functional role of calpain-1 in platelet spreading.

Publications

Targeted gene inactivation reveals a functional role of calpain-1 in platelet spreading.

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