Activation of C-Kinase η through Its Cholesterol-3-sulfate-Dependent Phosphorylation by Casein Kinase I in Vitro(Biochemistry/Molecular Biology)

概要

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The physiological correlation between casein kinase I (CK-I) and an isoform η of protein kinase C (C-kinase η) was investigated in vitro, since it has been reported that (i) chollesterol-3-sulfate (CH-3S) effectively activates C-kinase η rather than the other isoforms (C-kinase e and C-kinase δ) in vitro; and (ii) CK-I efficiently phosphorylates CH-3S-binding proteins, such as high mobility group protein 1 (HMG1), in the presence of CH-3S in vitro. We found that (i) CK-I phosphorylated Thr in preference to Ser on recombinant human C-kinase isoform η (rhC-kinase η) in the presence of CH-3S; (ii) this phosphorylation was selectively inhibited by CK-I-7 (a CK-I inhibitor); and (iii) the activity (phosphorylation of protamine sulfate) of rhC-kinase η was approx. 3.2-fold stimulated by its full phosphorylation by CK-I in the presence of 3μM CH-3S. These results suggest that CK-I is a protein kinase responsible for the activation of rhC-kinase η in the presence of CH-3S in vitro.
公益社団法人日本薬学会の論文
2004-01-01