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Rag GTPase subfamily of Ras-related GTPases Rag GTPases (ras-related GTP-binding proteins) constitute a unique subgroup of the Ras superfamily, playing an essential role in regulating amino acid-induced target of rapamycin complex 1 (TORC1) kinase signaling, exocytic cargo sorting at endosomes, and epigenetic control of gene expression. This subfamily consists of RagA and RagB as well as RagC and RagD that are closely related. Saccharomyces cerevisiae encodes single orthologs of metazoan RagA/B and RagC/D, Gtr1 and Gtr2, respectively. Dimer formation is important for their cellular function; these domains form heterodimers, as RagA or RagB dimerizes with RagC or RagD, and similarly, Gtr1 dimerizes with Gtr2. In response to amino acids, the Rag GTPases guide the TORC1 complex to activate the platform containing Rheb proto-oncogene by driving the relocalization of mTORC1 from discrete locations in the cytoplasm to a late endosomal and/or lysosomal compartment that is Rheb-enriched and contains Rab-7. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",