Glutamate substitutions at a PKA consensus site are consistent with inactivation of calpain by phosphorylation

FEBS Letters

Wells, Alan²  Elce, John S¹  Jia, Zongchao¹  Smith, Scott D¹  Huynh, Kassidy K¹ 

[1] Department of Biochemistry, Queen's University, Kingston, ON, Canada K7L 4V1;Department of Pathology, University of Pittsburgh, S713 Scaife Terrace and Lothrop St., Pittsburgh, PA 15261, USA

关键词: Calpain phosphorylation;    Calpain regulation;    Extracellular signal-regulated kinase;    Cyclic adenosine monophosphate-dependent kinase;    DSC;    differential scanning calorimetry;    ERK;    extracellular signal-regulated kinase;    PKA;    cyclic adenosine monophosphate-dependent kinase;   

DOI  :  10.1016/S0014-5793(03)00361-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Regulation of calpain by phosphorylation has often been suggested, but has proved difficult to detect. Calpains extracted from mammalian tissue are reported to contain 2–4 mol phosphate/mol of enzyme distributed over multiple sites, but phosphate groups are not detectable in the X-ray structures of recombinant calpain. Some serine and threonine residues in the large subunit of rat m-calpain were converted to aspartic or glutamic acid residues, at sites suggested by previous studies, to assess the probable effects of phosphate groups on the enzyme. Expression of the mutant calpains in Escherichia coli, and their heat stabilities, did not differ from those of the wild-type enzyme. m-Calpains with the mutations Ser50Asp, Ser50Glu, Ser67Glu, and Thr70Glu had the same specific activity and Ca²⁺ requirement as the wild-type enzyme. In contrast, Ser369Asp-, Ser369Glu-, and Thr370Glu-m-calpain were inactive. This result is consistent with the recent report that phosphorylation at position 369 or 370 in vivo reduced m-calpain activation.

【 授权许可】

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