Phosphorylation of human pleckstrin on Ser-113 and Ser-117 by protein kinase C.
During platelet activation, receptor-coupled phospholipid hydrolysis stimulates protein kinase C (PKC) and results in the phosphorylation of several proteins, the most prominent being pleckstrin. Pleckstrin is composed of two repeated domains, now called pleckstrin homology (PH) domains, separated by a spacer region that contains several consensus PKC phosphorylation sites. To determine the role of PKC-dependent phosphorylation in pleckstrin function, we mapped the phosphorylation sites in vivo of wild-type and site-directed mutants of pleckstrin expressed in COS cells. Phosphorylation was found to occur almost exclusively on Ser-113 and Ser-117 within the sequence 108-KFARKS*TRRS*IRL-120. Phosphorylation of these sites was confirmed by phosphorylation of the corresponding wild-type and mutant synthetic peptides in vitro.
Craig
K L
KL
Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
Harley
C B
CB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001798:Blood Proteins / Q000737:chemistry* / Q000378:metabolism*; D002460:Cell Line; D002522:Chlorocebus aethiops; D003062:Codon; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000737:chemistry / Q000302:isolation & purification; D010750:Phosphoproteins; D010766:Phosphorylation; D017354:Point Mutation; D011493:Protein Kinase C / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012694:Serine; D014162:Transfection; D014357:Trypsin
D001798:Blood Proteins; D003062:Codon; D010446:Peptide Fragments; D010748:Phosphopeptides; D010750:Phosphoproteins; D011994:Recombinant Proteins; C039077:platelet protein P47; D012694:Serine; D011493:Protein Kinase C; D014357:Trypsin