1.Evidence for Cyclooxygenase-2 Association with Caveolin-3 in Primary Cultured Rat Chondrocytes.
Jin Oh KWAK ; Woon Kyu LEE ; Hyun Woo KIM ; Sun Mi JUNG ; Kwang Jin OH ; Sang Yong JUNG ; Yang Hoon HUH ; Seok Ho CHA
Journal of Korean Medical Science 2006;21(1):100-106
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 CdCl2 (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.
Animals
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Animals, Newborn
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Blotting, Western
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Cadmium Chloride/pharmacology
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Caveolae/drug effects/metabolism/ultrastructure
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Caveolin 3/*genetics/metabolism
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Cell Membrane/drug effects/metabolism
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Cells, Cultured
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Chondrocytes/cytology/drug effects/*metabolism
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Cyclooxygenase 2/*genetics/metabolism
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Gene Expression
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Immunoprecipitation
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Microscopy, Confocal
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Microscopy, Electron
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RNA, Messenger/genetics/metabolism
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Rats
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Reverse Transcriptase Polymerase Chain Reaction