Title : Glycosylation regulates turnover of
cyclooxygenase-2
Abstract :
- Cyclooxygenase-2 ( COX-2) catalyzes the rate-limiting step in the prostanoid biosynthesis pathway, converting arachidonic acid into prostaglandin H(2)
- COX-2 exists as 72 and 74kDa glycoforms, the latter resulting from an additional oligosaccharide chain at residue Asn(580)
- In this study, Asn(580) was mutated to determine the biological significance of this variable glycosylation
- COS-1 cells transfected with the mutant gene were unable to express the 74kDa glycoform and were found to accumulate more COX-2 protein and have five times greater COX-2 activity than cells expressing both glycoforms
- Thus, COX-2 turnover appears to depend upon glycosylation of the 72kDa glycoform