Apoprotein A-1 is a cofactor independent substrate of protein kinase C.
Apoprotein A-1 (apo A-1), the predominant protein constituent of high density lipoproteins (HDL), was phosphorylated by protein kinase C (PKC). Optimal phosphorylation of lipid-free apo A-1 occurs in the absence of calcium, phosphatidyl serine (PS), and diolein (DO). However, HDL-bound apo A-1 was not phosphorylated by PKC. Furthermore, addition of either native or reconstituted HDL particles to lipid-free apo A-1 resulted in a concentration-dependent inhibition of phosphorylation. It appears that the phosphorylatable sites on apo A-1 are involved in hydrophobic interaction with the lipids of HDL. Apo A-1 is a novel substrate of PKC because it does not require calcium and lipid cofactors for optimal phosphorylation.
Holian
O
O
Department of Surgery, University of Illinois College of Medicine, Chicago 60680.
Kumar
R
R
Attar
B
B
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016632:Apolipoprotein A-I; D001054:Apolipoproteins A / Q000378:metabolism*; D001345:Autoradiography; D001921:Brain / Q000201:enzymology*; D002850:Chromatography, Gel; D007700:Kinetics; D008075:Lipoproteins, HDL / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A; D008075:Lipoproteins, HDL; D010761:Phosphorus Radioisotopes; D000255:Adenosine Triphosphate; D011493:Protein Kinase C