In unstimulated mouse 3T3-L1 adipocytes, perilipin is localized to the surfaces of cytosolic lipid particles as a complex with CGI-58. Catecholamine stimulation (and by inference glucagon stimulation) is associated with rapid dissociation of the complex and relocalization of the CGI-58 protein away from the lipid particle. The stoichiometry of the complex is unknown. Dissociation of the perilipin:CGI-58 complex appears to precede perilipin phosphorylation, although the molecular link between these two steps is unknown (Subramanian et al. 2004).
The interaction of human CGI-58 and perilipin on the lipid particle surface has not been studied in detail, so the human reaction is inferred from the well-studied mouse one. The observation that humans homozygous for CGI-58 mutations suffer from Chanarin-Dorfman Syndrome, characterized by the abnormal accumulation of triacylglycerol droplets in most tissues (Lefevre et al. 2001), provides indirect evidence that human and mouse CGI-58 proteins have similar functions.