title: Rapid production of platelet-activating factor is induced by protein kinase Cα-mediated phosphorylation of lysophosphatidylcholine acyltransferase 2 protein.
abstract: Platelet-activating factor (PAF), a potent proinflammatory lipid mediator, is synthesized rapidly in response to extracellular stimuli by the activation of acetyl-CoA:lyso-PAF acetyltransferase (lyso-PAFAT). We have reported previously that lyso-PAFAT activity is enhanced in three distinct ways in mouse macrophages: rapid activation (30 s) after PAF stimulation and minutes to hours after LPS stimulation. Lysophosphatidylcholine acyltransferase 2 (LPCAT2) was later identified as a Ca(2+)-dependent lyso-PAFAT. However, the mechanism of rapid lyso-PAFAT activation within 30 s has not been elucidated. Here we show a new signaling pathway for rapid biosynthesis of PAF that is mediated by phosphorylation of LPCAT2 at Ser-34. Stimulation by either PAF or ATP resulted in PKCα-mediated phosphorylation of LPCAT2 to enhance lyso-PAFAT activity and rapid PAF production. Biochemical analyses showed that the phosphorylation of Ser-34 resulted in augmentation of Vmax with minimal Km change. Our results offer an answer for the previously unknown mechanism of rapid PAF production.
authors.affiliation: From the Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan, the Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, and.
authors.forename: Ryo
authors.initials: R
authors.lastname: Morimoto
authors.affiliation: From the Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan, the Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan hshindou-tky@umin.net.
authors.forename: Hideo
authors.initials: H
authors.lastname: Shindou
authors.affiliation: From the Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Tarui
authors.affiliation: From the Department of Lipid Signaling, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan, the Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, and.
authors.forename: Takao
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D003412:Cricetulus; D055785:Gene Knockdown Techniques; D007249:Inflammation / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010766:Phosphorylation / Q000276:immunology; D010972:Platelet Activating Factor / Q000378:metabolism*; D051571:Protein Kinase C-alpha / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology
chemical_list: D008070:Lipopolysaccharides; D010972:Platelet Activating Factor; D012694:Serine; D008243:1-Acylglycerophosphocholine O-Acyltransferase; C000592232:LPCAT2 protein, mouse; D051571:Protein Kinase C-alpha
keywords: Enzyme Catalysis; Inflammation; Lysophospholipid Acyltransferase; Macrophages; Membrane Lipids; Phosphorylation; Platelet-activating Factor; Protein Kinase C (PKC)
references.citation: FASEB J. 2010 Dec;24(12):4929-38
references.pmid: 20705908
references.citation: J Biol Chem. 1990 Apr 15;265(11):6296-300
references.pmid: 2318854
references.citation: Biochem Biophys Res Commun. 2013 Jun 28;436(2):306-12
references.pmid: 23743196
references.citation: J Biochem. 1996 Oct;120(4):838-44
references.pmid: 8947850
references.citation: Annu Rev Pathol. 2008;3:99-126
references.pmid: 18039143
references.citation: J Biol Chem. 1999 Feb 26;274(9):5469-73
references.pmid: 10026159
references.citation: Prog Lipid Res. 2000 Jan;39(1):41-82
references.pmid: 10729607
references.citation: J Biol Chem. 1993 May 5;268(13):9194-7
references.pmid: 8486620
references.citation: J Biol Chem. 1988 Apr 5;263(10):4607-11
references.pmid: 2832400
references.citation: Blood. 2012 Mar 15;119(11):2533-44
references.pmid: 22138510
references.citation: J Biol Chem. 1995 Dec 29;270(52):31345-52
references.pmid: 8537406
references.citation: J Biol Chem. 1980 Nov 10;255(21):10256-60
references.pmid: 7430122
references.citation: J Biol Chem. 1994 Jan 28;269(4):2877-86
references.pmid: 7507929
references.citation: J Biol Chem. 2010 Sep 24;285(39):29857-62
references.pmid: 20663880
references.citation: Anal Biochem. 1976 May 7;72:248-54
references.pmid: 942051
references.citation: Biochem J. 1993 Sep 1;294 ( Pt 2):335-7
references.pmid: 8373348
references.citation: J Biol Chem. 1985 Dec 5;260(28):15194-9
references.pmid: 3905792
references.citation: Proc Natl Acad Sci U S A. 2008 Feb 26;105(8):2830-5
references.pmid: 18287005
references.citation: Mol Cell Proteomics. 2006 Apr;5(4):749-57
references.pmid: 16340016
references.citation: Nature. 1997 Dec 11;390(6660):618-22
references.pmid: 9403692
references.citation: J Biol Chem. 2009 Jan 2;284(1):1-5
references.pmid: 18718904
references.citation: Immunity. 2008 Apr;28(4):581-9
references.pmid: 18342553
references.citation: Biochemistry. 1980 May 27;19(11):2396-404
references.pmid: 6770893
references.citation: J Cell Mol Med. 2013 Dec;17(12):1554-65
references.pmid: 24373549
references.citation: J Biol Chem. 1990 Oct 15;265(29):17381-4
references.pmid: 2170377
references.citation: J Biol Chem. 1997 Sep 5;272(36):22898-904
references.pmid: 9278453
references.citation: J Biol Chem. 1988 Feb 15;263(5):2217-22
references.pmid: 2828363
references.citation: Annu Rev Biochem. 2001;70:281-312
references.pmid: 11395409
references.citation: J Biol Chem. 2005 Mar 11;280(10):9083-7
references.pmid: 15618224
references.citation: J Pharmacol Exp Ther. 1994 Nov;271(2):824-31
references.pmid: 7965802
references.citation: J Biol Chem. 2007 Mar 2;282(9):6532-9
references.pmid: 17182612
references.citation: Annu Rev Pharmacol Toxicol. 2009;49:123-50
references.pmid: 18834304
references.citation: Biochem Biophys Res Commun. 2000 May 19;271(3):812-7
references.pmid: 10814544
references.citation: J Biol Chem. 1995 Oct 27;270(43):25481-7
references.pmid: 7592717
references.citation: J Clin Invest. 2011 Apr;121(4):1484-96
references.pmid: 21436586
references.citation: J Biol Chem. 2008 Apr 25;283(17):11097-106
references.pmid: 18285344
references.citation: Anal Biochem. 2005 Jul 1;342(1):134-43
references.pmid: 15958190
references.citation: FASEB J. 2012 Jan;26(1):169-80
references.pmid: 21968070
references.citation: J Biol Chem. 1991 Dec 15;266(35):23856-62
references.pmid: 1660886
references.citation: Physiol Rev. 2008 Oct;88(4):1341-78
references.pmid: 18923184
references.citation: J Biochem. 1997 Jul;122(1):1-16
references.pmid: 9276665
references.citation: J Immunol. 2005 Jul 15;175(2):1177-83
references.pmid: 16002720
references.citation: Nature. 1981 Apr 9;290(5806):527-8
references.pmid: 7219539
references.citation: Annu Rev Biochem. 1997;66:475-509
references.pmid: 9242915