Evidence for cyclooxygenase-2 association with caveolin-3 in primary cultured rat chondrocytes.
The purpose of this study was to demonstrate the cellular localization of cyclooxygenase-2 (COX-2) and caveolin-3 (Cav-3) in primarily cultured rat chondrocytes. In normal rat chondrocytes, we observed relatively high levels of Cav-3 and a very low level of COX-2 mRNA and protein. Upon treating the chondrocytes with 5 microM of CdCl(2) (Cd) for 6 hr, the expressions of COX-2 mRNA and protein were increased with the decreased Cav-3 mRNA and protein expressions. The detergent insoluble caveolae-rich membranous fractions that were isolated from the rat chondrocytes and treated with Cd contained the both proteins of both COX-2 and Cav-3 in a same fraction. The immuno-precipitation experiments showed complex formation between the COX-2 and Cav-3 in the rat chondrocytes. Purified COX-2 with glutathione S-transferase-fused COX-2 also showed complex formation with Cav-3. Confocal and electron microscopy also demonstrated the co-localization of COX-2 and Cav-3 in the plasma membrane. The results from our current study show that COX-2 and Cav-3 are co-localized in the caveolae of the plasma membrane, and they form a protein-protein complex. The co-localization of COX-2 with Cav-3 in the caveolae suggests that the caveolins might play an important role for regulating the function of COX-2.
Kwak
Jin-Oh
JO
Department of Pharmacology and Toxicology, College of Medicine, Inha University, Incheon.
Lee
Woon Kyu
WK
Kim
Hyun-Woo
HW
Jung
Sun-Mi
SM
Oh
Kwang-Jin
KJ
Jung
Sang-Yong
SY
Huh
Yang Hoon
YH
Cha
Seok Ho
SH
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D019256:Cadmium Chloride / Q000494:pharmacology; D021941:Caveolae / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D051244:Caveolin 3 / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D047468:Immunoprecipitation; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
D051244:Caveolin 3; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D019256:Cadmium Chloride