Phosphorylation of human serum amyloid A protein by protein kinase C

Nel A.E.
De Beer M.C.
Shephard E.G.
Strachan A.F.
Vandenplas M.L.
De Beer F.C.
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Monokine-induced hepatic secretion of serum amyloid A protein (apo-SAA), an acute-phase reactant, is followed by rapid association with high-density lipoprotein (HDL) in plasma. Plasma clearance of apo-SAA is more rapid than any of the other HDL apolipoproteins. It has been shown that, of the acute-phase HDL3 apolipoproteins, apo-SAA preferentially associated with neutrophil membranes. HDL apolipoproteins have been shown to activate protein kinase C in endothelial cells. We therefore investigated potential phosphorylation of HDL3 apolipoproteins by protein kinase C. Apo-SAA was the only apolipoprotein phosphorylated (K(m) = 12 mM). Phosphorylation of the apo-SAA-containing HDL3 particle was selective for the more basic isoforms of apo-SAA (pI 7.0, 7.4, 7.5 and 8.0), with more acidic isoforms being phosphorylated when delipidated acute-phase apolipoproteins were used as substrate. However, phosphorylation was not in itself responsible for the establishment of the apo-SAA isoforms.
acute phase protein, amyloid protein, apolipoprotein, high density lipoprotein, monokine, protein kinase c, human, priority journal, protein phosphorylation, Amino Acids, Amyloid Protein SAA, Apolipoproteins, Cell Line, Electrophoresis, Polyacrylamide Gel, Human, Isoelectric Focusing, Peptide Mapping, Phosphorylation, Protein Kinase C, Support, Non-U.S. Gov't
Biochemical Journal