{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nRRAGA is an essential component of the heterodimeric Rag GTPases that functions as a molecular switch to relay nutrient status to mTOR complex 1 (mTORC1). In response to amino acid sufficiency, the active, GTP‐loaded RRAGA (in heterodimer with a GDP‐bound partner) directly engages the RAPTOR subunit, thereby promoting mTORC1 recruitment to the lysosomal surface and triggering anabolic signaling cascades. Structural analyses have revealed that RRAGA’s nucleotide binding status is specifically detected by key domains of RAPTOR, ensuring that only the appropriate (active) Rag heterodimer engages mTORC1."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "4"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its role in mTORC1 recruitment, RRAGA activity is dynamically modulated by several interlinked regulatory mechanisms. Post-translational modifications such as K63-linked ubiquitination—mediated by E3 ligases like RNF152 and Skp2—promote the recruitment of the GATOR1 complex, which in turn activates RRAGA’s GTPase activity leading to its inactivation and downregulation of mTORC1 signaling. Moreover, specific protein partners (for example, DYNLT, WDR35, and even factors like C9orf72) interact with RRAGA to fine-tune its lysosomal trafficking and signal termination. These intersubunit communications and accessory protein interactions underscore a complex network that rigorously couples nutrient sensing to mTORC1 activity."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "5", "end_ref": "13"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nPerturbations in RRAGA function have significant physiological consequences. Mutations in RRAGA—exemplified by a p.Leu60Arg variant linked to autosomal dominant cataracts—disrupt normal mTORC1 signaling, leading to altered autophagy, cell growth, and lysosomal dynamics. Furthermore, dysregulation of RRAGA-mediated pathways affects the lysosomal degradation of key cell surface proteins (e.g., CD47), thereby contributing to aberrant cellular clearance and broader metabolic imbalances. Collectively, these studies highlight the critical importance of RRAGA in maintaining cellular homeostasis through its precise control of mTORC1 activity."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "14", "end_ref": "17"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Lu Deng, Cong Jiang, Lei Chen, et al. 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