Activation of C-Kinase .ETA. through Its Cholesterol-3-sulfate-Dependent Phosphorylation by Casein Kinase I in Vitro
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Accession number;04A0042361
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| Title;Activation of C-Kinase .ETA. through Its Cholesterol-3-sulfate-Dependent Phosphorylation by Casein Kinase I in Vitro |
| Author;
OKANO M
(Kitasato Univ., Sagamihara, Jpn)
YOKOYAMA T
(Kitasato Univ., Sagamihara, Jpn)
MIYANAGA T
(Kitasato Univ., Sagamihara, Jpn)
OHTSUKI K
(Kitasato Univ., Sagamihara, Jpn)
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Journal Title;Biol Pharm Bull
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Journal Code:S0989A
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ISSN:0918-6158
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VOL.27;NO.1;PAGE.109-112(2004)
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| Figure&Table&Reference;FIG.5, REF.19 |
| Pub. Country;Japan |
| Language;English |
| Abstract;The physiological correlation between casein kinase I (CK-I) and an isoform .ETA. of protein kinase C (C-kinase .ETA.) was investigated in vitro, since it has been reported that (i) cholesterol-3-sulfate (CH-3S) effectively activates C-kinase .ETA. rather than the other isoforms (C-kinase .EPSILON. and C-kinase .DELTA.) 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 .ETA. (rhC-kinase .ETA.) 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 .ETA. was approx. 3.2-fold stimulated by its full phosphorylation by CK-I in the presence of 3 .MU.M CH-3S. These results suggest that CK-I is a protein kinase responsible for the activation of rhC-kinase .ETA. in the presence of CH-3S in vitro. (author abst.) |
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