The authors report that NAMPT, the rate-limiting enzyme in the NAD+ salvage pathway, is a direct substrate of multiple proto-oncogenic tyrosine kinases. Kinases identified include ALK, the insulin receptor, IGF1R, and PDGFRA. Phosphoproteomic analyses supported these kinase–substrate relationships and implicated oncogenic fusion kinases in NAMPT regulation.
Phosphoproteomics pinpointed tyrosine 188 (Y188) on NAMPT as the major phosphorylation site. This phosphorylation event was detected in the context of several kinases, including the oncogenic fusion kinase NPM1::ALK. The report emphasizes Y188 as a key residue mediating kinase-driven modifications of NAMPT.
NAMPT was found to interact physically with NPM1::ALK in multiple cellular compartments: the cytoplasm, nucleus, and mitochondria. These interactions suggest that kinase-mediated regulation of NAMPT may occur across subcellular locations and could influence compartment-specific NAD+ metabolism.
Phosphorylation at Y188 enhanced NAMPT catalytic activity and increased production of NMN and NAD+, with downstream effects on cellular metabolism. Conversely, a Y188F substitution (nonphosphorylatable mutant) reduced enzymatic activity. Cells expressing the Y188F mutant exhibited decreased proliferation and clonogenicity in the reported experiments, supporting a functional role for this phosphorylation site in promoting cancer cell growth.
Dimerization of NAMPT was required for full phosphorylation and enzymatic function. Disruption of dimer formation impaired both phosphorylation at Y188 and NAMPT catalytic activity, indicating that dimerization and tyrosine phosphorylation act cooperatively to activate NAMPT. The data suggest a model in which dimer assembly facilitates access or conformation required for kinase targeting and catalytic efficiency.
Interactome analyses revealed that phosphorylation and dimerization remodel NAMPT-associated protein networks. Phosphorylated, dimeric NAMPT was enriched for associations with metabolic and redox regulators, whereas monomeric NAMPT preferentially associated with factors involved in ribosome biogenesis. These distinct interaction patterns imply that post-translational modification and oligomeric state direct NAMPT toward different functional modules within the cell.
Pharmacologic inhibition of NAMPT suppressed growth of lymphoma cells that were sensitive to ALK inhibition as well as cells resistant to ALK inhibitors. In addition, NAMPT inhibition enhanced the efficacy of ALK-targeted therapy in the reported models. The authors conclude that kinase-dependent activation of NAMPT represents a metabolic vulnerability in oncogene-driven cancers and that combining NAMPT inhibition with kinase inhibitors could be a therapeutic strategy.
Authors disclosed competing interests: two authors are inventors on a patent related to NAMPT treatment, and one author reported research funding and consulting relationships with industry and is an inventor on a related patent. Other authors declared no competing interests. The manuscript notes that research funding agencies did not participate in study conceptualization, design, data collection, analysis, decision to publish, or manuscript preparation. The work was posted as a bioRxiv preprint on August 15, 2026.
The abstract provides mechanistic highlights and conceptual findings but does not report specific experimental protocols, quantitative effect sizes, inhibitor identities or concentrations, cell line panels, or in vivo results. These methodological and quantitative details were not reported in the abstract and would require consultation of the full preprint for verification and deeper assessment.
This preprint describes cooperative activation of NAMPT by tyrosine phosphorylation (notably at Y188) and dimerization, linking oncogenic tyrosine kinases such as ALK and NPM1::ALK to enhanced NMN/NAD+ biosynthesis and pro-growth metabolic programs in cancer. Functional experiments reported that blocking phosphorylation or dimerization reduces NAMPT activity and tumor cell fitness, and that NAMPT inhibitors can suppress tumor cell growth and potentiate ALK inhibitor responses. The findings identify kinase-dependent NAMPT activation as a candidate metabolic vulnerability in oncogene-driven malignancies. For full experimental detail and quantitative data, refer to the complete preprint.