Premium
Protein kinase C mutants in the auto‐inhibitory region exhibit two distinct properties
Author(s) -
Muramatsu Masa-aki,
Kaibuchi Kozo,
Arai Ken-ichi
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81371-r
Subject(s) - protein kinase c , xenopus , cytosol , microbiology and biotechnology , phosphorylation , jurkat cells , kinase , biology , biochemistry , signal transduction , mutant , germinal vesicle , protein kinase a , in vivo , chemistry , enzyme , genetics , gene , t cell , immune system , meiosis
To define the role of the auto‐inhibitory region of protein kinase C (PKC), 22 ‐ 23 ‐Gly 24 ‐Ala 25 ‐Leu 26 ‐Arg 27 , site‐directed mutations were introduced into the basic residues. Three mutants, PKC Ala22,23 , PKC Ala27 and PKC Ala22,23,27 , apparently fell into two distinct types with regard to their biochemical properties and biological activities, as judged by the enhancement of a c‐ fos promoter in Jurkat cells and by the initiation of germinal vesicle breakdown (GVBD) in Xenopus laevis oocytes. (i) PKC Alu22,23 and PKC Ala27 had activators independent in vitro kinase activity, high phosphorylation levels in vivo, and localized in both cytosolic and particulate fractions. These mutants were not fully biologically active. (ii) PKC Ala22,23,27 had a low phosphorylation level in vivo, was found predominantly in the particulate fraction and was the most biologically active. These results suggest that basic residues in the auto‐inhibitory domain account for the regulation of kinase activity and the cytosolic retention of PKC. The particulate association or the cytosolic clearance of PKC may facilitate signal transduction in the cell.