Recombinant Human LAMTOR3 Protein: Function & Research Use

Recombinant Human LAMTOR3 Protein is a research-grade recombinant protein representing a critical scaffold subunit of the lysosomal Ragulator complex that facilitates mTORC1 activation and MAPK signaling in response to amino acid availability.

Protein Name

Late Endosomal/Lysosomal Adaptor and MAPK and mTOR Activator 3 (LAMTOR3)

Also Known As

MP1, ROBLD3, p14-MP1 complex partner

Biological Role

Scaffold subunit of the pentameric Ragulator complex; required for lysosomal recruitment and activation of mTORC1; involved in MAPK/ERK signaling

Protein Form

Recombinant human protein produced in a heterologous expression system

Primary Research Applications

Biochemical assays, protein–protein interaction studies, structural studies, antibody validation, mTOR and MAPK pathway research

Related SKU

rp371363 — Recombinant Human LAMTOR3 Protein (Aladdin Scientific)

Biological Background and Function of LAMTOR3

LAMTOR3, also designated MP1 (MEK Partner 1), is a member of the LAMTOR (Late Endosomal/Lysosomal Adaptor, MAPK and mTOR Activator) protein family. It is encoded by the LAMTOR3 gene in humans and functions as a structural and scaffolding component within the pentameric Ragulator complex, which also includes LAMTOR1 (p18), LAMTOR2 (p14), LAMTOR4, and LAMTOR5.

The Ragulator complex is anchored to the cytoplasmic face of late endosomes and lysosomes, where it serves as a critical platform for the amino acid-dependent activation of mechanistic target of rapamycin complex 1 (mTORC1). Under nutrient-replete conditions, the Ragulator acts as a guanine nucleotide exchange factor (GEF) for the RagA/B GTPases, promoting the recruitment of mTORC1 to the lysosomal surface where it becomes activated by Rheb. LAMTOR3 contributes to the structural integrity of this complex and is essential for proper lysosomal localization of the Ragulator.

Beyond its role in mTORC1 signaling, LAMTOR3/MP1 was originally identified as a scaffold protein that facilitates MEK1–ERK1 signaling on late endosomes. This endosomal MAPK signaling compartment is spatially and temporally distinct from plasma membrane-initiated MAPK cascades, suggesting that LAMTOR3 helps specify the subcellular location and duration of ERK activation. These dual roles in mTOR and MAPK pathways make LAMTOR3 a protein of broad interest across cell biology, cancer research, and metabolic disease.

Recombinant Protein Characteristics and Quality Considerations

Recombinant Human LAMTOR3 Protein (Aladdin Scientific, SKU: rp371363) is produced using heterologous expression systems to yield a soluble, functional form of the human LAMTOR3 polypeptide suitable for in vitro research applications. Recombinant forms of LAMTOR3 are typically expressed with an affinity purification tag (such as His-tag or GST-tag) to facilitate single-step chromatographic purification and to enable tag-based pulldown assays.

Key quality attributes researchers should confirm prior to experimental use include: (1) Purity — typically assessed by SDS-PAGE or HPLC; high-purity preparations minimize non-specific effects in binding assays; (2) Endotoxin levels — critical for cell-based assays where lipopolysaccharide contamination can confound results; (3) Biological activity — ideally validated by a functional assay such as protein–protein interaction with a known binding partner (e.g., LAMTOR2/p14 or MEK1); and (4) Storage and stability — lyophilized or liquid formulations each have distinct handling requirements. Researchers should consult the product datasheet for lot-specific certificates of analysis (CoA).

Note: Specific numerical values for purity, endotoxin content, molecular weight, and expression host for the Aladdin Scientific rp371363 product should be confirmed directly from the current product datasheet or certificate of analysis, as these specifications may vary by lot.

Research Applications of Recombinant Human LAMTOR3 Protein

Recombinant Human LAMTOR3 Protein is a versatile tool across multiple experimental modalities in cell biology, biochemistry, and signal transduction research:

• Protein–Protein Interaction Studies: LAMTOR3 directly interacts with LAMTOR2 (p14) to form the MP1-p14 dimer, a core unit within the Ragulator complex. Recombinant LAMTOR3 is used in co-immunoprecipitation (co-IP), pulldown assays, surface plasmon resonance (SPR), and isothermal titration calorimetry (ITC) to map binding interfaces and characterize interaction affinities.
• Structural Biology: Recombinant LAMTOR3 and its complexes with binding partners are amenable to crystallography and cryo-electron microscopy studies aimed at resolving the molecular architecture of the Ragulator complex.
• mTORC1 Pathway Research: LAMTOR3 is used to reconstitute Ragulator sub-complexes in vitro for mechanistic studies of RagGTPase nucleotide exchange and mTORC1 lysosomal recruitment.
• MAPK/ERK Signaling Studies: As a scaffold for MEK1-ERK1 on late endosomes, recombinant LAMTOR3 supports studies into compartment-specific MAPK signaling.
• Antibody Validation and Immunoassay Development: Purified recombinant LAMTOR3 serves as a positive control antigen for Western blot, ELISA, and immunofluorescence assay development and antibody specificity validation.
• Drug Discovery: As a component of nutrient-sensing machinery dysregulated in cancer and metabolic disorders, LAMTOR3 is a potential target for screening small molecule inhibitors of the Ragulator–Rag GTPase–mTORC1 axis.

Handling, Storage, and Experimental Tips

To preserve the activity and integrity of Recombinant Human LAMTOR3 Protein, the following general best practices are recommended (always defer to product-specific datasheet instructions):

• Storage: Upon receipt, briefly centrifuge the vial before opening. Store lyophilized protein at –20 °C or –80 °C as specified. Reconstituted or liquid preparations should be aliquoted to avoid repeated freeze–thaw cycles, which can lead to aggregation and loss of activity.
• Reconstitution: Use the recommended reconstitution buffer (typically sterile PBS or the buffer specified in the CoA). Allow the protein to fully dissolve before use; avoid vortexing vigorously.
• Working Concentrations: Titrate the protein empirically for each specific assay. For binding studies, a range of concentrations spanning the expected K_d should be tested.
• Carrier Protein: For dilute preparations, adding BSA (0.1–0.5%) can stabilize the protein and reduce adsorptive losses to tube surfaces.
• Quality Check: Verify integrity by SDS-PAGE under reducing and non-reducing conditions before critical experiments. Compare to the expected molecular weight and purity as stated on the CoA.

Researchers should consult Aladdin Scientific's technical support team for application-specific guidance and the most current product specifications for rp371363.

Frequently asked questions

What is LAMTOR3 and why is it important in cell biology?

LAMTOR3 (also called MP1) is a subunit of the pentameric Ragulator complex located on the lysosomal membrane. It plays a dual role: as a scaffold for MEK1-ERK1 (MAPK) signaling on late endosomes, and as a structural component required for mTORC1 activation in response to amino acid availability. Its involvement in both nutrient sensing and growth factor signaling makes it relevant to cancer, metabolic disease, and autophagy research.

What expression system is used to produce Recombinant Human LAMTOR3 Protein (rp371363)?

The specific expression host for Aladdin Scientific SKU rp371363 should be confirmed from the current product datasheet or certificate of analysis. Common expression systems for LAMTOR3 include E. coli, baculovirus/insect cell, and mammalian cell systems, each offering different trade-offs in terms of yield, post-translational modifications, and solubility. Please contact Aladdin Scientific technical support or refer to the product page for confirmed lot-specific details.

Can Recombinant Human LAMTOR3 Protein be used for antibody validation?

Yes. Purified recombinant LAMTOR3 protein is well-suited as a positive control antigen for validating anti-LAMTOR3 antibodies in applications such as Western blot, ELISA, and immunofluorescence. Using the recombinant protein as a defined standard helps confirm antibody specificity and sensitivity prior to use in complex biological samples such as cell lysates or tissue sections.

How should Recombinant Human LAMTOR3 Protein be stored to maintain stability?

General best practice is to store lyophilized protein at –20 °C or –80 °C, and to aliquot reconstituted or liquid preparations to avoid repeated freeze–thaw cycles. Always refer to the specific storage conditions stated on the product datasheet or certificate of analysis for rp371363, as optimal conditions depend on the formulation buffer and protein concentration.

Is LAMTOR3 relevant to cancer or disease research?

Yes. LAMTOR3's roles in mTORC1 nutrient sensing and endosomal MAPK/ERK signaling place it at the intersection of pathways frequently dysregulated in cancer and metabolic disorders. Aberrant mTORC1 and ERK signaling contribute to tumor growth, drug resistance, and metabolic reprogramming, making Ragulator complex components including LAMTOR3 subjects of interest in oncology and precision medicine research.

References

1. Sancak Y, Bar-Peled L, Zoncu R, Markhard AL, Nada S, Sabatini DM. Ragulator-Rag complex targets mTORC1 to the lysosomal surface and is necessary for its activation by amino acids. Cell. 2010;141(2):290-303. doi:10.1016/j.cell.2010.02.024
2. Bar-Peled L, Schweitzer LD, Zoncu R, Sabatini DM. Ragulator is a GEF for the rag GTPases that signal amino acid levels to mTORC1. Cell. 2012;150(6):1196-1208. doi:10.1016/j.cell.2012.07.032
3. Teis D, Wunderlich W, Huber LA. Localization of the MP1-MAPK scaffold complex to endosomes is mediated by p14 and required for signal transduction. Dev Cell. 2002;3(6):803-814. doi:10.1016/S1534-5807(02)00364-7

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