LAMTOR1 is a critical lysosomal membrane adaptor protein that serves as the anchoring subunit of the Ragulator complex 12. Its primary function is to tether the Ragulator complex to lysosomal membranes and facilitate mTORC1 activation in response to amino acids. LAMTOR1 acts as a guanine nucleotide exchange factor for Rag GTPases and mediates their recruitment to lysosomes, creating a scaffold that enables mTORC1 translocation to lysosomes where it becomes activated 3. Beyond mTORC1 signaling, LAMTOR1 regulates lysosomal calcium homeostasis through direct inhibition of the TRPML1 channel, controlling dendritic lysosomal trafficking and synaptic plasticity independently of mTORC1 4. LAMTOR1 also governs lysosomal degradation pathways; it facilitates PD-L1 degradation via interaction with HRS to suppress exosomal PD-L1 release in lung cancer 5, and regulates cGAS abundance through lysosomal sequestration 6. Therapeutically, LAMTOR1 inhibition increases autophagy and ameliorates metabolic dysfunction-associated fatty liver disease by suppressing mTORC1 7. LAMTOR1 dysregulation contributes to cancer progression through enhanced mTORC1 activation 8 and embryonic development 9, making it a potential therapeutic target for metabolic, immune, and neoplastic diseases.