TIP47PLIN3

TIP47PLIN3, also known as TIP47 or perilipin-3 (PLIN3), is a member of the PAT family of lipid droplet-associated proteins. In humans, the PLIN3 gene encodes this protein. TIP47 was originally identified as a Rab9 effector required for trafficking between late endosomes and the trans-Golgi network, and it later came to be recognized as a perilipin that localizes to lipid droplets in many cell types.

In endosomal traffic, TIP47 binds the GTP-bound Rab9 and functions as an effector that supports retrograde transport of mannose-6-phosphate receptors from late endosomes to the TGN, helping maintain proper receptor sorting and cargo trafficking.

In relation to lipid droplets, TIP47/PLIN3 is thought to coat droplets and influence their formation or turnover, possibly by modulating the access of lipases to stored neutral lipids. Members of the PAT family share similar domain organization, including the PAT domain, and TIP47 lacks a transmembrane region, targeting droplets through amphipathic helices and other protein-protein interactions. The protein is broadly expressed across tissues, reflecting roles in both endosomal trafficking and lipid droplet biology.

Genetic and clinical correlations are not strongly established; TIP47/PLIN3 is primarily studied for its cellular trafficking functions and its participation in lipid droplet biology. Altered expression has been reported in various experimental contexts, but no specific inherited disorder is conclusively linked to PLIN3 mutations.