What Is LAMTOR1? Gene, Protein Structure, and Aliases

LAMTOR1, encoded by the LAMTOR1 gene (also designated C11orf59), is a 161-amino-acid palmitoylated and myristoylated peripheral membrane protein that localizes predominantly to the cytoplasmic face of late endosomes and lysosomes. It is commonly referred to by the alias p18 in the literature, and also appears under the identifiers ROBLD3 and FRICAT.

LAMTOR1 serves as the essential membrane anchor of the five-subunit Ragulator complex (comprising LAMTOR1 through LAMTOR5). Its N-terminal lipid modifications (N-myristoylation and palmitoylation) tether the entire Ragulator assembly to the lysosomal surface. Structurally, LAMTOR1 contains a roadblock domain that mediates protein–protein interactions within the complex, enabling scaffold functions critical for signal transduction.

Loss-of-function studies have demonstrated that LAMTOR1 is indispensable for proper lysosomal positioning and for the recruitment of mTORC1 to the lysosomal membrane—the obligate site of mTORC1 activation by Rag GTPases.

Role of LAMTOR1 in mTORC1 and Nutrient-Sensing Signaling

The mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth, metabolism, and autophagy. Its activation at the lysosomal membrane is tightly coupled to intracellular amino acid availability through the Ragulator–Rag GTPase axis, in which LAMTOR1 plays a central scaffolding role.

When amino acids are present, the Ragulator complex acts as a guanine nucleotide exchange factor (GEF) for the Rag GTPases (RagA/B and RagC/D). Activated Rag heterodimers recruit mTORC1 to the lysosomal surface, where the small GTPase Rheb stimulates full kinase activation. LAMTOR1, as the anchor subunit, is required to position the entire Ragulator–Rag module at the lysosome. Additionally, LAMTOR1 interacts with the vacuolar H⁺-ATPase (v-ATPase), which has been proposed to act as a luminal amino acid sensor relaying signals to the Ragulator.

Beyond amino acid sensing, LAMTOR1 has been shown to scaffold MAP kinase (MAPK/ERK) signaling at the endolysosomal compartment, reflecting its broader designation as a MAPK and mTOR Activator. Perturbation of LAMTOR1 disrupts both mTORC1 and ERK pathway outputs, underscoring its multifunctional nature in growth-factor and nutrient signaling integration.

Research Applications of Recombinant Human LAMTOR1 Protein

Recombinant Human LAMTOR1 Protein (Aladdin Scientific, SKU: rp375518) enables a broad range of in vitro and cell-based studies. Key application areas include:

• Protein–protein interaction studies: Co-immunoprecipitation (co-IP), pull-down assays, and surface plasmon resonance (SPR) experiments to map LAMTOR1 interactions with other Ragulator subunits, Rag GTPases, and v-ATPase subunits.
• Biochemical reconstitution: Reconstitution of the Ragulator complex or subsets thereof to study GEF activity toward Rag GTPases in cell-free systems.
• ELISA and immunoassay development: Use as a calibration standard or coating antigen for developing quantitative immunoassays measuring LAMTOR1 levels in biological samples.
• Antibody validation: Positive control antigen for verifying the specificity of anti-LAMTOR1 antibodies in Western blot, immunofluorescence, and immunohistochemistry applications.
• Structural biology: Substrate for X-ray crystallography or cryo-electron microscopy studies investigating Ragulator architecture.
• Drug discovery: Tool protein for high-throughput screening assays targeting the mTORC1 nutrient-sensing pathway in oncology and metabolic disease contexts.

Researchers are encouraged to optimize buffer conditions, storage, and reconstitution protocols according to the product datasheet for best experimental results.

Handling, Storage, and Quality Considerations

Recombinant proteins require careful handling to preserve activity and prevent degradation. The following general guidelines apply to Recombinant Human LAMTOR1 Protein (rp375518); always consult the specific product datasheet for definitive specifications:

• Storage temperature: Typically –80 °C for long-term storage; avoid repeated freeze–thaw cycles by preparing single-use aliquots upon first use.
• Reconstitution: Lyophilized preparations should be reconstituted in the recommended buffer (consult datasheet) and allowed to equilibrate at room temperature briefly before use.
• Protein concentration: Verify concentration by absorbance at 280 nm (A₂₈₀) or a validated colorimetric assay (e.g., BCA) upon receipt and after reconstitution.
• Sterility and contamination: Work under aseptic conditions when the protein will be used in cell culture experiments to prevent microbial contamination.
• Quality control: Aladdin Scientific performs SDS-PAGE and, where applicable, functional assays to confirm purity and activity of each lot. Lot-specific certificates of analysis (CoA) are available upon request.

For technical support regarding experimental design or troubleshooting, contact Aladdin Scientific's technical support team.

LAMTOR1 in Disease and Therapeutic Context

Dysregulation of LAMTOR1-mediated mTORC1 signaling has been implicated in multiple pathological contexts, making it a subject of growing therapeutic interest:

• Cancer metabolism: Hyperactivation of mTORC1 is a hallmark of many cancers. Because LAMTOR1 is essential for amino acid-dependent mTORC1 recruitment, alterations in its expression or function may contribute to oncogenic mTORC1 activity. Studies in various cancer cell lines have explored LAMTOR1 as a potential vulnerability in nutrient-sensing pathways.
• Immune cell function: LAMTOR1 has been reported to regulate mTORC1 and ERK signaling in immune cells, including dendritic cells and T cells, affecting their activation, differentiation, and cytokine production. Conditional knockout models have highlighted the role of LAMTOR1 in innate and adaptive immunity.
• Lysosomal storage disorders: As a lysosomal membrane-associated protein, perturbation of LAMTOR1 can affect lysosomal biogenesis and function, with potential relevance to lysosomal storage diseases.
• Autophagy regulation: Given that mTORC1 is a primary suppressor of autophagy, LAMTOR1-dependent mTORC1 regulation indirectly governs autophagic flux, relevant to neurodegeneration and aging research.

Recombinant Human LAMTOR1 Protein provides a valuable in vitro tool for mechanistic studies aimed at understanding these disease-relevant pathways and evaluating potential therapeutic interventions.