Fig. 3
From: Perilipins: a diversity of intracellular lipid droplet proteins
Hormonal regulation of PLIN1-dependent lipolysis in adipocytes. Under unstimulated conditions, PLIN1 is associated with CGI-58, and the PLIN1-CGI-58 complex localizes with ATGL on the surfaces of large LDs. However, ATGL and HSL are inactive under these conditions and lipolysis does not proceed. When the adipocytes are stimulated with adrenergic agonists, hormone sensitive lipase (HSL) and PLIN1 are phosphorylated by activated PKA. Subsequently, phosphorylated PLIN1 releases CGI-58, which binds and activates ATGL. Concurrently, numerous small LDs containing PLIN2 are generated from the ER, and ATGL-CGI-58 complexes localize on the small LDs and actively hydrolyze TG. Phosphorylated HSL also moves to LD surfaces and participate in lipolysis