Phosphorylation of hormone-sensitive lipase by cyclic GMP-dependent protein kinase.

In intact rat adipocytes hormone-sensitive lipase has been shown to be phosphorylated on serine residues in two different phosphorylation sites: a regulatory site phosphorylated by cyclic AMP-dependent protein kinase and a basal site, which does not directly affect the enzyme activity, phosphorylated by cyclic AMP-independent protein kinase(s) [(1984) Proc. Natl. Acad. Sci. USA 81, 3317-3321]. Cyclic GMP-dependent protein kinase catalyzed the phosphorylation of the same two phosphorylation sites on the isolated enzyme, at serine residues. Both sites were phosphorylated at about the same rate, with the hormone-sensitive lipase activity concomitantly enhanced.