title: The role of calpain in the regulation of ADAM17-dependent GPIbalpha ectodomain shedding.
abstract: There are evidence that both a disintegrin and metalloproteinase 17 (ADAM17) and calpain are involved in platelet glycoprotein (GP)Ibalpha ectodomain cleavage. However, the relationship between the two enzymes in the shedding process remains unclear. Here we show that calcium ionophore A23187- and alpha-thrombin-induced GPIbalpha shedding is completely inhibited by the metalloproteinase inhibitor GM6001, whereas it is only partially inhibited by calpain inhibitors. Calpain activator dibucaine-induced GPIbalpha shedding was completely inhibited by both metalloproteinase and calpain inhibitors. On the other hand, calpain inhibitors did not inhibit GPIbalpha shedding induced by the reagents that specifically activate ADAM17. Furthermore, A23187-induced GPIbalpha shedding in Chinese hamster ovary cells expressing wild-type or mutant GPIb-IX was also partially inhibited by calpain inhibitors and almost completely inhibited by GM6001. Therefore, these data indicate that calpain plays an important role in the regulation of ADAM17-dependent GPIbalpha ectodomain shedding in both platelets and nucleated cells.
authors.affiliation: Beihang University, Haidian District, Beijing, China.
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Quanwei
authors.initials: Q
authors.lastname: Shi
authors.forename: Rong
authors.initials: R
authors.lastname: Yan
authors.forename: Guanglei
authors.initials: G
authors.lastname: Liu
authors.forename: Weilin
authors.initials: W
authors.lastname: Zhang
authors.forename: Kesheng
authors.initials: K
authors.lastname: Dai
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism; D000072198:ADAM17 Protein; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism; D016466:CHO Cells; D000001:Calcimycin / Q000494:pharmacology*; D002154:Calpain / Q000037:antagonists & inhibitors*; D006224:Cricetinae; D003412:Cricetulus; D003992:Dibucaine / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007476:Ionophores / Q000494:pharmacology*; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D009154:Mutation; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000235:genetics / Q000378:metabolism*; D016608:Talin / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism
chemical_list: D000779:Anesthetics, Local; D004151:Dipeptides; D007476:Ionophores; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D019038:Platelet Glycoprotein GPIb-IX Complex; D016608:Talin; D000001:Calcimycin; D006861:Hydrogen Peroxide; D013917:Thrombin; D002154:Calpain; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D003992:Dibucaine