Open AccessMultiple isoforms of a protein kinase C inhibitor (KCIP‐1/14‐3‐3) from sheep brain
Author(s) -
TOKER Alex,
SELLERS Lynda A.,
AMESS Bob,
PATEL Yasmina,
HARRIS Alan,
AITKEN Alastair
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb16946.x
Subject(s) - protein kinase c , map2k7 , cyclin dependent kinase 2 , mitogen activated protein kinase kinase , c raf , protein kinase a , biochemistry , cyclin dependent kinase 9 , gene isoform , map kinase kinase kinase , kinase , casein kinase 1 , casein kinase 2 , biology , activator (genetics) , cgmp dependent protein kinase , protein phosphorylation , chemistry , gene
A potent inhibitor of protein kinase C (PKC), inhibitor protein‐1 (KCIP‐1), isolated form sheep brain has been shown to consist of eight isoforms by reverse‐phase HPLC. Direct protein sequence analysis has revealed these to be the same as those of 14‐3‐3 protein, described as an activator of tyrosine and tryptophan hydroxylases involved in neurotransmitter biosynthesis. The N‐termini of KCIP‐1 isoforms were shown to be acetylated, and secondary structure predictions revealed a high degree of α‐helix with an amphipathic nature. KCIP‐1 showed no inhibitory activity towards protein kinase M (the catalytic fragment of PKC) and had no effect on the activities of three other protein kinases, cAMP‐dependent protein kinase, Ca 2+ /calmodulin‐dependent protein kinase II and casein kinase 2. Four forms of KCIP‐1 were shown to be substrates for PKC in vitro , but none were phosphorylated by the other protein kinases mentioned above.