The role of palmitoyl-protein thioesterase in the palmitoylation of endothelial nitric oxide synthase.
Palmitoylation of eNOS is required for targeting to plasmalemmal caveolae and agonist-promoted depalmitoylation leads to eNOS translocation, modifying the agonist response. To date, one palmitoyl-protein thioesterase (PPT) has been purified and cloned. To explore the role of PPT in eNOS palmitoylation, we first established that PPT mRNA and protein are expressed in endothelial cells. Coexpression of PPT and eNOS in heterologous systems (COS and Sf-9 cells) resulted in a marked reduction in [3H]palmitate labeling of eNOS. We found, however, that co-expression did not alter subcellular targeting of eNOS, but that [3H]palmitate incorporation into cellular lipids, in particular palmitoyl-CoA, was significantly reduced. These results suggest that while PPT expression can significantly alter cellular lipid metabolism, it has no effect on eNOS palmitoylation.
Michel
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JB
Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. Michel@calvin.bwh.harvard.edu
Michel
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D000818:Animals; D019556:COS Cells; D002451:Cell Compartmentation; D004727:Endothelium / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D010168:Palmitates / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D018411:Spodoptera; D013869:Thiolester Hydrolases / Q000378:metabolism
D010168:Palmitates; D019001:Nitric Oxide Synthase; D013869:Thiolester Hydrolases; C095299:palmitoyl-protein thioesterase