Phosphorylation of p36 in vitro with pp60src. Regulation by Ca2+ and phospholipid.
P36 is a major substrate of the tyrosine protein kinases. P36 isolated from bovine intestine was used in phosphorylation reactions with pp60src. Phosphorylation was stimulated 3-5-fold by Ca2+, however the Km was the same (2.5 microM) at high or low Ca2+. Although the level of free Ca2+ needed for this enhanced phosphorylation was 10(-4)-10(-3) M, phosphatidylserine shifted the Ca2+ sensitivity to the 10(-6)-10(-5) M range. Independent evidence suggested that p36 interacts directly with liposomes containing phosphatidylserine. This raises the possibility that p36, like c-kinase, is a Ca2+-activated, phospholipid-dependent protein.
J R
JR
Glenney
D000818:Animals; D017302:Annexins; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D007422:Intestines / Q000032:analysis; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D015688:Oncogene Protein pp60(v-src); D010716:Phosphatidylinositols / Q000494:pharmacology; D010718:Phosphatidylserines / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology*; D010766:Phosphorylation; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012191:Retroviridae Proteins / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D017302:Annexins; D008565:Membrane Proteins; D010716:Phosphatidylinositols; D010718:Phosphatidylserines; D010743:Phospholipids; D012191:Retroviridae Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src); D002118:Calcium