FEBS Letters | |
Presence in many mammalian tissues of an identical major cytosolic substrate (M r 100000) for calmodulin‐dependent protein kinase | |
Palfrey, H.Clive1  | |
[1] Department of Pharmacological and Physiological Sciences, University of Chicago, 947 E. 58th Street, Chicago, IL 60637, USA | |
关键词: Calcium; Calmodulin; Protein kinase; Phosphorylase; CaM; calmodulin; 100 kDa; major phosphoprotein of M r 100000; EGTA; ethylene glycol bis (β-aminoethylether)-N; N; N′; N′-tetraacetic acid; SAP; Staphylococcus aureus protease; SAC; Staphylococcus aureus cells; | |
DOI : 10.1016/0014-5793(83)81142-9 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Incubation of cytosol fractions from a variety of mammalian tissues (heart, liver, lung, adrenal, spleen and skeletal muscle) with Ca2+ (0.5 mM) in the presence of γ-[32P]ATP resulted in the phosphorylation of a prominent substrate of M r ∼ 100000 (100 kDa). One-dimensional peptide maps and two-dimensional tryptic fingerprints of the phosphoprotein from these sources were identical. A single major phosphopeptide was generated by trypsin and was determined to contain exclusively phosphothreonine. The 100 kDa substrate could be distinguished from glycogen phosphorylase (M r ∼ 97000) by a number of criteria including phosphopeptide mapping and by its failure to bind either to glycogen or to a specific antiphosphorylase antibody. The Ca2+-dependent protein kinase responsible for phosphorylation of the 100 kDa protein appeared to be a calmodulin (CaM)-requiring enzyme in that it could be inhibited in cytosol extracts by trifluoperazine (IC 50 6–16 μM) and that exogenous CaM was necessary for 100 kDa phosphorylation in CaM-depleted cytosol. These results suggest that a rise in intracellular Ca2+ resulting in an activation of CaM-dependent protein kinase leads to the phosphorylation of a common 100 kDa substrate in many tissues.
【 授权许可】
Unknown
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