Evidence for cyclooxygenase-2 association with caveolin-3 in primary cultured rat chondrocytes

• Published in: Journal of Korean medical science 2006, 21(1), , pp.100-106
• Main Authors: Kwak, Jin-Oh, Lee, Woon Kyu, Kim, Hyun-Woo, Jung, Sun-Mi, Oh, Kwang-Jin, Jung, Sang-Yong, Huh, Yang Hoon, Cha, Seok Ho
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Blotting, Western; Cadmium Chloride - pharmacology; Caveolae - drug effects; Caveolae - metabolism; Caveolae - ultrastructure; Caveolin 3 - genetics; Caveolin 3 - metabolism; Cell Membrane - drug effects; Cell Membrane - metabolism; Cells, Cultured; Chondrocytes - cytology; Chondrocytes - drug effects; Chondrocytes - metabolism; Cyclooxygenase 2 - genetics; Cyclooxygenase 2 - metabolism; Gene Expression; Immunoprecipitation; Microscopy, Confocal; Microscopy, Electron; Original; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; 의학일반
• ISSN: 1011-8934; 1598-6357
• DOI: 10.3346/jkms.2006.21.1.100

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.