Steroidogenic cells store cholesteryl esters, precursors for steroid hormone synthesis, in
intracellular lipid droplets. Cholesteryl ester hydrolysis is activated by protein kinase A and
catalyzed by cholesteryl esterase. The esterase is similar, if not identical, to hormone-
sensitive lipase in adipocytes where an analogous lipolytic mechanism occurs. Perilipins,
proteins located exclusively at lipid droplet surfaces in adipocytes, are polyphosphorylated
by protein kinase A in response to lipolytic stimuli, suggesting a role for these proteins in …