Post-translationally modified 14-3-3 isoforms and inhibition of protein kinase C.
This report compares the ability of individual members of the 14-3-3 protein family to inhibit particular protein kinase C (PKC) isoforms. We also show that two of these 14-3-3 isoforms (alpha and delta) specific to mammalian and avian brain are in vivo post-translationally modified forms of beta and zeta respectively. The presence of this modification enhances the activity of 14-3-3 as an inhibitor of protein kinase C nearly two fold. A method for analysing isoforms of 14-3-3 on acid-urea gels is also described. This permits the complete separation of all major isoforms and their unequivocal identification by a range of isoform specific antisera. The activity of recombinant 14-3-3 and isoforms renatured by a novel method after separation by reverse phase HPLC are compared. The effects of diacylglycerol and the phorbol ester, PMA (phorbol 1 2-myristate 13 acetate) on the inhibition suggest that one of the sites of interaction of 14-3-3 may be the cysteine-rich (C1) domain in PKC.
Aitken
A
A
Laboratory of Protein Structure, National Institute for Medical Research, Mill Hill, London, UK.
Howell
S
S
Jones
D
D
Madrazo
J
J
Martin
H
H
Patel
Y
Y
Robinson
K
K
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D012756:Sheep; D013329:Structure-Activity Relationship; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D004791:Enzyme Inhibitors; D010455:Peptides; D011506:Proteins; D014446:Tyrosine 3-Monooxygenase; D011493:Protein Kinase C