Ras-related GTP-binding protein A

RRAGA encodes Ras-related GTP-binding protein A (RagA), a guanine nucleotide-binding protein that acts as a molecular switch in nutrient sensing. RagA forms heterodimeric complexes with RagC or RagD and cycles between GDP-bound (inactive) and GTP-bound (active) states, directly regulating the mTORC1 signaling cascade in response to amino acid availability (UniProt: Q7L523). When GTP-bound, RagA promotes recruitment of mTORC1 to lysosomes, enabling its activation by RHEB. The protein participates in the RCC1/Ran-GTPase pathway and may contribute to TNF-mediated cell death signaling.

RRAGA is widely expressed and functions as a critical nutrient sensor within cellular signaling networks. No disease-associated variants are annotated in UniProt for this protein.

RRAGA demonstrates reduced abundance in Alzheimer's Disease brain tissue. In post-mortem AD brain compared to age-matched controls, RRAGA was downregulated across subcellular fractions (mean log2 fold-change −0.29; Chaparral AD proteomics). This decrease may indicate impaired mTORC1 signaling and dysregulated amino acid sensing in AD pathology, potentially contributing to altered metabolic homeostasis observed in neurodegenerative disease.