PMID: 9648871Jul 2, 1998Paper

Tissue transglutaminase is an in situ substrate of calpain: regulation of activity

Journal of Neurochemistry
J ZhangG V Johnson

Abstract

Tissue transglutaminase (tTG) is a calcium-dependent enzyme that catalyzes the transamidation of specific polypeptide-bound glutamine residues, a reaction that is inhibited by GTP. There is also preliminary evidence that, in situ, calpain and GTP may regulate tTG indirectly by modulating its turnover by the calcium-activated protease calpain. In the present study, the in vitro and in situ proteolysis of tTG by calpain, and modulation of this process by GTP, was examined. tTG is an excellent substrate for calpain and is rapidly degraded. Previously it has been demonstrated that GTP binding protects tTG from degradation by trypsin. In a similar manner, guanosine-5'-O-(3-thiotriphosphate) protects tTG against proteolysis by calpain. Treatment of SH-SY5Y cells with 1 nM maitotoxin, which increases intracellular calcium levels, resulted in a significant increase in in situ TG activity, with only a slight decrease in tTG protein levels. In contrast, when GTP levels were depleted by pretreating the cells with tiazofurin, maitotoxin treatment resulted in an approximately 50% decrease in tTG protein levels, and a significant decrease in TG activity, compared with maitotoxin treatment alone. Addition of calpain inhibitors inhibited the d...Continue Reading

Citations

Oct 5, 2006·Journal of Neurochemistry·Qinghua ChenRodney P Guttmann
Dec 9, 2004·Journal of Neurochemistry·Craig D C Bailey, Gail V W Johnson
Mar 3, 2012·Digestive and Liver Disease : Official Journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver·Giuseppe D'ArgenioMarco Romano
Aug 14, 2001·Biochemical and Biophysical Research Communications·S W KimK S Ha
Dec 12, 2001·Neurochemistry International·Mathieu LesortGail V W Johnson
Dec 12, 2001·Neurochemistry International·Soo Youl KimPeter M Steinert
Apr 5, 2000·Progress in Neurobiology·M LesortG V Johnson
Sep 11, 1999·The International Journal of Biochemistry & Cell Biology·J S Chen, K Mehta
Jul 16, 2003·Biochemical and Biophysical Research Communications·Gerald M O'NeillAthar H Chishti
Jan 4, 2012·Pharmacology & Therapeutics·Hilary Grosso, M Maral Mouradian

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