Growth hormone-regulated TBC protein 1, TBC1 domain family member 6, GRTP1, TBC1D6
Pituitary growth hormone (GH), also designated somatotropin, plays a crucial role in stimulating and controlling the growth, metabolism and differentiation of many mammalian cell types by modulating the synthesis of multiple mRNA species. These effects are mediated by the binding of GH to its membranebound receptor, GHR, and involve a phosphorylation cascade that results in the modulation of numerous signaling pathways. GRTP1 (growth hormoneregulated TBC protein 1), also designated TBC1 domain family member 6, is a 336 amino acid protein with expression modulated by growth hormone. The TBC1 domain of GRTP1 is a region that is notably conserved among GTPaseactivating proteins, which characteristically play a role in the cell cycle and mitosis coordination. Interestingly, expression of GRTP1 is significantly upregulated in post-puberty testis and then maintained in the adult, suggesting that the germ cell may be the major site of GRTP1 function. There are two isoforms of GRTP1, which are a result of alternative splicing events.
