identical to that of yeast Rab7a. Using Northern Blot Analysis, Vitelli et al. (1996) found that RAB7a was expressed as 1.7- and 2.5-kb transcripts in all cell lines examined but that there was a large difference in the total amount of RAB7a mRNA among the cell lines. Regulation It is linked that RAB7a levels and function were independent of melanocyte lineage-specific transcription factors (MITF) but recent research has shown that SOX10 (a neuroectodermal master modulator) and MYC (an oncogene) are the major regulators. Rab7a is regulated by SOX10 and MYC respectively in a lineage-specific wiring. Studies show that RAB7a can be specifically up regulated through MITF-independent manners like changing levels of SOX10 or MYC to affect tumor proliferation especially in melanoma[14]. In studies using antisense RNA, downregulation of RAB7 gene expression in HeLa cells using antisense RNA induces severe cell vacuolation that resembles the phenotype seen in fibroblasts from patients with Chédiak–Higashi syndrome. In the presence of growth factor, growth factor inhibition of mammalian Rab7 had no effect on nutrient transporter expression in mouse pro-B-lymphocytic cells. In growth factor-deprived cells, however, blocking Rab7 function prevented the clearance of glucose and amino acid transporter proteins from the cell surface. When Rab7 was inhibited, growth factor-deprived cells maintained their mitochondrial membrane potential and displayed prolonged, growth factor-independent, nutrient-dependent cell survival. The authors concluded that RAB7 functions as a proapoptotic protein by limiting cell-autonomous nutrient uptake. Interactions RAB7A has been shown to interact with RILP and CHM. RILP has been shown to have a key role in the control of transport to degradative compartments along with Rab7 and may link Rab7 function to the cytoskeleton. RILP plays the role of a downstream effector for Rab7 and together both of these proteins act to regulate late endocytic traffic. RAB7A directly interacts with Rubicon when RAB7A is bound to GTP. Rubicon is a negative regulator of autophagy. Other key interactions include RAC1 (By similarity), NTRK1/TRKA (By similarity), C9orf72 (By similarity), CHM (the substrate-binding subunit of the Rab geranylgeranyltransferase complex), and RILP, as well as PSMA7, RNF115 and FYCO1. Interacts with the PIK3C3/VPS34-PIK3R4 complex. The GTP-bound form interacts with OSBPL1A and CLN3. Rab7A was also shown to interact with the Retromer Complex, most likely through the Vps35 subunit. Clinical significance RAB7 is a small GTPase that has the potential of causing malignancy from over 35 tumor types. It is found that RAB7 is an early induced