Proliferative effect of phospholipase A2 in rat chondrocyte via its specific binding sites.
We studied the presence of specific binding sites for pancreatic-type group I phospholipase A2 (PLA2-I), EC 3.1.1.4, and a PLA2-I action on the DNA synthesis of rat chondrocytes. Rat chondrocytes, derived from the xiphisternum of adult rats, had a single class of PLA2-I binding site with an equilibrium binding constant value of 0.9 nM and a maximum binding capacity of 53.9 fmol/10(6) cells. PLA2-I alone did not show any proliferative effect, however, PLA2-I dose-dependently stimulated thymidine incorporation in DNA in the presence of basic fibroblast growth factor (bFGF). The mammalian mature type of PLA2s-I specifically recognized the binding sites in these cells and had a synergistic effect on DNA synthesis with bFGF, whereas its inactive zymogen and group II PLA2 showed much lesser activities. The type-specific action of PLA2s implicated the involvement of PLA2-I specific binding sites in this activation process.
Kishino
J
J
Shionogi Research Laboratories, Shionogi & Co., Ltd. Osaka, Japan.
Tohkin
M
M
Arita
H
H
D000818:Animals; D001665:Binding Sites; D002356:Cartilage / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects*; D007213:Indomethacin / Q000494:pharmacology; D007700:Kinetics; D010741:Phospholipases A / Q000378:metabolism* / Q000494:pharmacology*; D054467:Phospholipases A2; D051381:Rats; D011919:Rats, Inbred Strains; D013552:Swine
D010741:Phospholipases A; D054467:Phospholipases A2; D007213:Indomethacin