Location of sites in human lipocortin I that are phosphorylated by protein tyrosine kinases and protein kinases A and C.
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Varticovski L, Chahwala SB, Whitman M, Cantley L, Schindler D, Chow EP, Sinclair LK, Pepinsky RB
Location of sites in human lipocortin I that are phosphorylated by protein tyrosine kinases and protein kinases A and C.
Biochemistry. 1988 May 17;27(10):3682-90.
- PubMed ID
- 2457390 [ View in PubMed]
- Abstract
Lipocortin I is a 39-kilodalton membrane-associated protein that in A431 cells is phosphorylated on tyrosine in response to epidermal growth factor (EGF). We have used recombinant human lipocortin I as a substrate for several protein kinases and identified phosphorylated residues by a combination of peptide mapping and sequence analysis. Lipocortin I was phosphorylated near the amino terminus at Tyr-21 by recombinant pp60c-src. The same tyrosine residue was phosphorylated by polyoma middle T/pp60c-src complex, by recombinant pp50v-abl, and with A431 cell membranes by the EGF receptor/kinase. The primary site of phosphorylation by protein kinase C was also near the amino terminus at Ser-27. The major site of phosphorylation by adenosine cyclic 3',5'-phosphate dependent protein kinase was on the carboxy-terminal half of the molecule at Thr-216. These sites are compared to the phosphorylation sites previously located in the structurally related protein lipocortin II.