Ragulator complex protein LAMTOR1

LAMTOR1 (Ragulator complex protein 1) is a 161-amino acid scaffolding protein that serves as a key component of the Ragulator complex, a multiprotein assembly involved in nutrient sensing and cell growth signaling (UniProt: Q6IAA8). As the primary membrane anchor for the Ragulator complex, LAMTOR1 recruits and activates the small GTPases Rag and mediates their localization to lysosomal membranes, enabling downstream activation of mTORC1—a central signaling hub that integrates amino acid availability with cell growth and proliferation.

LAMTOR1 localizes to late endosomes and lysosomes, where it participates in amino acid sensing, endosomal receptor recycling, and MAPK pathway regulation (UniProt: Q6IAA8). The protein may additionally contribute to cholesterol homeostasis and embryonic stem cell differentiation through alternative Rag-activation pathways independent of canonical mTOR signaling.

In Alzheimer's disease, LAMTOR1 is elevated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.39 across multiple subcellular fractions in TMT-labeled proteomics (Chaparral AD proteomics). This upregulation suggests potential dysregulation of mTORC1 signaling or lysosomal function in the AD brain, though the functional significance remains to be characterized.