NMT1 Human
Description
Oncogenic Signaling
NMT1 overexpression is observed in colorectal, hepatocellular, breast, and lung cancers. It promotes tumor growth by myristoylating oncoproteins (e.g., c-Src, LAMTOR1) to enhance kinase activity, lysosomal function, and mTORC1 signaling . Inhibition reduces proliferation and induces apoptosis in cancer cell lines .
Immune Regulation
NMT1 modulates innate immune responses by myristoylating proteins involved in pathogen recognition (e.g., ARF6) and cytokine signaling. It also facilitates HIV-1 assembly by modifying viral proteins .
Metabolic Regulation
NMT1-mediated myristoylation is required for autophagic flux and lysosomal degradation, impacting cellular metabolism under stress conditions .
Clinical and Therapeutic Relevance
Association with Diseases
Inhibitors in Development
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Desloratadine: Binds Asn246 in NMT1, blocking VILIP3 myristoylation and NFκB signaling in HCC .
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DDD85646: Targets the myristoyl-CoA binding pocket, showing efficacy in preclinical models .
Research Advances
Proteomic Studies
iTRAQ-based analyses identified NMT1-regulated proteins (e.g., AHSG, ALB) whose stability depends on myristoylation. Knockdown alters lysosomal function and ER stress responses .
6. Recombinant NMT1 Proteins
Recombinant human NMT1 is used to study enzyme kinetics and inhibitor screening. Key products include:
| Product | Host | Tag | Purity | Source |
|---|---|---|---|---|
| TP300594 (Origene) | HEK293T | Myc/DDK | >80% | Full-length |
| ENZ-842 (ProSpec) | E. coli | N-terminal His | >85% | 1-496 aa |
Future Directions
Product Specs
Q&A
NMT1 Human: Research-Focused FAQs
How do researchers validate NMT1-specific activity in cellular models, given the presence of NMT2?
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Isoform-specific antibodies: Western blotting with antibodies targeting unique NMT1/NMT2 epitopes .
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Knockdown/rescue experiments: siRNA-mediated NMT1 silencing followed by overexpression of wild-type or catalytically dead mutants (e.g., C159A) .
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Click chemistry: Metabolic labeling with alkyne-myristate analogs allows detection of N-myristoylated proteins via fluorescence or mass spectrometry .
Data contradiction: NMT1 and NMT2 may have overlapping substrates. Use dual knockdowns and substrate-specific assays (e.g., AHSG for NMT1, ALB for NMT2) .
What experimental approaches resolve contradictions in NMT1’s role in cancer progression?
NMT1 exhibits context-dependent effects:
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Pro-tumorigenic: Upregulates HIST1H4H and AHSG in liver cancer via POTEE-dependent N-myristoylation .
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Anti-tumorigenic: Suppresses ALB and TF in colorectal cancer .
Methodological solutions:
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Tissue-specific knockout models: Liver-specific Nmt1 deletion reduces hepatocellular carcinoma (HCC) growth .
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Organoid systems: Test NMT1 inhibition in patient-derived colorectal cancer organoids to reconcile in vitro vs. in vivo findings .
How does NMT1 regulate differential expression of NDP and NUP, and what are the implications for experimental design?
NMT1 suppresses NDP (e.g., AHSG) and stimulates NUP (e.g., ALB, TF) through:
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Interaction partners: RPL7A (binds NDP) and HBB (binds NUP) mediate opposing effects .
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N-myristoylation: Enhances protein stability and interaction affinity (Figure 2B–C in ).
Experimental considerations:
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Use co-immunoprecipitation (Co-IP) with RPL7A/HBB mutants to dissect motif dependencies (e.g., PPVxxAxxxxV) .
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Quantify protein half-lives via cycloheximide chase assays after NMT1 modulation .
What are the challenges in developing isoform-selective NMT1 inhibitors, and how can structural insights address them?
Challenges:
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High homology: NMT1 and NMT2 share >70% sequence identity in catalytic domains .
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Off-target effects: Non-selective inhibitors disrupt essential myristoylation in healthy cells .
Solutions:
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Covalent inhibitors: Target non-conserved cysteine residues (e.g., C159 in NMT1) .
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Peptide mimetics: Design compounds that exploit differences in substrate-binding pockets (e.g., indazole-based inhibitors) .
How do researchers assess NMT1’s role in immune cell differentiation, and what models are optimal?
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PBMC studies: Overexpression of NMT1 in peripheral blood mononuclear cells (PBMCs) correlates with adenomatous polyps and colorectal cancer .
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Mouse models: Conditional Nmt1 knockout in hematopoietic lineages impairs monocyte differentiation .
Methodology:
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Flow cytometry to track CD14+/CD16+ monocytes in PBMCs after NMT1 inhibition .
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RNA-seq to identify NMT1-dependent immune signaling pathways (e.g., TLR4/NF-κB) .
Data Table: Key Findings on NMT1 in Disease Contexts
How can researchers address conflicting data on NMT1’s substrate specificity across studies?
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Standardized assays: Use recombinant NMT1 and defined peptide libraries to compare myristoylation efficiency .
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Machine learning: Train models on structural data (e.g., PDB 6Y2F) to predict substrate preferences .
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Cross-validation: Confirm hits with orthogonal methods (e.g., click chemistry + LC-MS/MS) .
Product Science Overview
N-Myristoyltransferase 1 (NMT1) is an essential enzyme that catalyzes the covalent attachment of myristic acid, a 14-carbon saturated fatty acid, to the N-terminal glycine residue of substrate proteins. This process, known as N-myristoylation, is crucial for the proper functioning of various proteins involved in signal transduction, apoptosis, and cellular trafficking .
NMT1 is a protein-coding gene that plays a pivotal role in the post-translational modification of proteins. The enzyme operates by transferring myristate from myristoyl-CoA to the N-terminal glycine of target proteins. This modification is irreversible and is essential for the full expression of the biological activities of several N-myristoylated proteins .
The catalytic domain of NMT1 contains an N-terminal region that acts as an inhibitory module. This region regulates the enzyme’s activity by modulating its catalytic efficiency. Removal of this N-terminal peptide has been shown to increase the enzyme’s activity, suggesting that it serves as a regulatory control element .
NMT1 is involved in various cellular processes, including signal transduction and apoptosis. It is essential for the proper functioning of several proteins, including the alpha subunit of the signal-transducing guanine nucleotide-binding protein (G protein). The enzyme’s activity is crucial for the biological activities of these proteins, making it a central switch in cellular signaling pathways .
NMT1 has attracted significant interest as a potential therapeutic target for cancer and infectious diseases. Specific inhibitors of NMT1 have been developed and are being explored for their therapeutic potential. These inhibitors can block N-myristoylation in cells, thereby affecting the function of N-myristoylated proteins and potentially providing a therapeutic benefit .
Recent studies have focused on the validation and invalidation of chemical probes for human NMT1. These studies have identified several compounds that can selectively inhibit NMT1 activity in cells. For example, IMP-1088 has been shown to deliver complete and specific inhibition of N-myristoylation in a range of cell lines .
Additionally, research has demonstrated that the N-terminal region of the catalytic domain of NMT1 acts as an inhibitory module. This finding suggests that the proteolytic processing of this region could provide a molecular mechanism for the physiological up-regulation of NMT1 activity .
