The linoleic acid derivative DCP-LA selectively activates PKC-epsilon, possibly binding to the phosphatidylserine binding site.
This study examined the effect of 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA), a newly synthesized linoleic acid derivative with cyclopropane rings instead of cis-double bonds, on protein kinase C (PKC) activity. In the in situ PKC assay with reverse-phase high-performance liquid chromatography, DCP-LA significantly activated PKC in PC-12 cells in a concentration-dependent (10 nM-100 microM) manner, with the maximal effect at 100 nM, and the DCP-LA effect was blocked by GF109203X, a PKC inhibitor, or a selective inhibitor peptide of the novel PKC isozyme PKC-epsilon. Furthermore, DCP-LA activated PKC in HEK-293 cells that was inhibited by the small, interfering RNA against PKC-epsilon. In the cell-free PKC assay, of the nine isozymes examined here, DCP-LA most strongly activated PKC-epsilon, with >7-fold potency over other PKC isozymes, in the absence of dioleoyl-phosphatidylserine and 1,2-dioleoyl-sn-glycerol; instead, the DCP-LA action was inhibited by dioleoyl-phosphatidylserine. DCP-LA also activated PKC-gamma, a conventional PKC, but to a much lesser extent compared with that for PKC-epsilon, by a mechanism distinct from PKC-epsilon activation. Thus, DCP-LA serves as a selective activator of PKC-epsilon, possibly by binding to the phosphatidylserine binding site on PKC-epsilon. These results may provide fresh insight into lipid signaling in PKC activation.
Kanno
Takeshi
T
Department of Physiology, Hyogo College of Medicine, Nishinomiya 663-8501, Japan.
Yamamoto
Hideyuki
H
Yaguchi
Takahiro
T
Hi
Rika
R
Mukasa
Takeshi
T
Fujikawa
Hirokazu
H
Nagata
Tetsu
T
Yamamoto
Satoshi
S
Tanaka
Akito
A
Nishizaki
Tomoyuki
T
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002210:Caprylates / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008041:Linoleic Acids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D016716:PC12 Cells; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051744:Protein Kinase C-epsilon / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013379:Substrate Specificity
C506022:8-(2-(2-pentyl-cyclopropylmethyl)cyclopropyl)octanoic acid; D002210:Caprylates; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D008041:Linoleic Acids; D010718:Phosphatidylserines; D034741:RNA, Small Interfering; C042511:1,2-dioleoylphosphatidylserine; C087857:protein kinase C gamma; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon