{"doi":"10.1101/2022.10.21.513220","title":"The mechanism of nicotinamide phosphoribosyltransferase whereby positive allosteric modulation elevates cellular NAD <sup>+</sup>","abstract":"ABSTRACT In aging and disease, cellular NAD + is depleted by catabolism to nicotinamide (NAM) and NAD + supple-mentation is being pursued to enhance human healthspan and lifespan. Activation of nicoti namide phosphoribosyl -transferase (NAMPT), the rate-limiting step in NAD + biosynthesis, has potential to increase salvage of NAM. Novel NAMPT positive allosteric modulators (N-PAMs) were discovered in addition to demonstration of NAMPT activati on by biogenic phenols. The mechanism of activation was revealed through synthesis of novel chemical probes, new NAMPT co-crystal structures, and enzyme kinetics. Binding to a rear channel in NAMPT regulates NAM binding and turnover, with biochemical observations being replicated by NAD + measurements in human cells. The mechanism of action of N-PAMs identifies, for the first time, the role of the rear channel in regulation of NAMPT turnover coupled to feedback inhibition by NAM. N-PAM inhibition of low affinity, non-productive NAM binding via the rear channel, causes a right-shif t in K I (NAM) that accompanies an increase in enzyme activity. Conversion of an N-PAM to a high-affinity l igand blocks both high and low affinity NAM binding, ablating enzyme activity. In the presence of an N-PAM, NAMPT boosts NAD + biosynthesis at higher NAM concentrations, in addition to relieving inhibition by NAD + . Since cellular stress often leads to enhanced catabolism of NAD + to NAM, this mechanism is relevant to supporting cellular N AD + levels in aging and disease. The tight regulation of cellular NAMPT is differentially regulated by N-PAMs and other activators, indicating that different classes of pharmacological activators may be engineered for cell and tissue selectivity.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2022,"id":304641,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.959,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":473684,"name":"Zhengnan Shen","orcid":"0000-0003-0276-7742","position":1,"is_corresponding":false},{"id":997549,"name":"Jesse Gordon-Blake","orcid":"0000-0001-8077-1240","position":2,"is_corresponding":false},{"id":352857,"name":"Hyun Lee","orcid":"0000-0003-2570-8120","position":3,"is_corresponding":false},{"id":854618,"name":"Megan S. Laham","orcid":"0000-0002-9803-3323","position":4,"is_corresponding":false},{"id":997550,"name":"Isabella S. Krider","orcid":"0009-0005-6444-7834","position":5,"is_corresponding":false},{"id":998057,"name":"Nicholas Christie","orcid":null,"position":6,"is_corresponding":false},{"id":696111,"name":"Martha Ackerman-Berrier","orcid":null,"position":7,"is_corresponding":false},{"id":998058,"name":"Christopher Penton","orcid":null,"position":8,"is_corresponding":false},{"id":998059,"name":"Natalie G. Knowles","orcid":null,"position":9,"is_corresponding":false},{"id":998060,"name":"Soumya Reddy Musku","orcid":null,"position":10,"is_corresponding":false},{"id":998061,"name":"Jiqiang Fu","orcid":null,"position":11,"is_corresponding":false},{"id":998062,"name":"Ganga Reddy Velma","orcid":null,"position":12,"is_corresponding":false},{"id":259834,"name":"Rui Xiong","orcid":"0000-0002-6350-9037","position":13,"is_corresponding":false},{"id":399125,"name":"Gregory R. J. Thatcher","orcid":"0000-0002-7757-1739","position":14,"is_corresponding":false},{"id":473685,"name":"Kiira Ratia","orcid":"0000-0002-4834-9207","position":0,"is_corresponding":true}],"reference_count":44,"raw_metadata":null,"created_at":"2026-07-19T00:32:32.651796Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}