{"doi":"10.1101/2021.05.24.445544","title":"Cellular calcium levels influenced by NCA-2 impact circadian period determination in <i>Neurospora</i>","abstract":"Abstract Intracellular calcium signaling has been implicated in control of a variety of circadian processes in animals and plants but its role in microbial clocks has remained largely cryptic. To examine the role of intracellular Ca 2+ in the Neurospora clock we screened knockouts of calcium transporter genes and identified a gene encoding a calcium exporter, nca-2 , uniquely as having significant period effects. Loss of NCA-2 results in an increase in cytosolic calcium level, and this leads to hyper-phosphorylation of core clock components, FRQ and WC-1, and a short period as measured by both the core oscillator and overt clock. Genetic analyses showed that mutations in certain frq phospho-sites, and in Ca 2+ -calmodulin-dependent kinase ( camk-2 ), are epistatic to nca-2 in controlling the pace of the oscillator. These data are consistent with a model in which elevated intracellular Ca +2 leads to increased activity of CAMK-2 leading to enhanced FRQ phosphorylation, accelerated closure of the circadian feedback loop, and a shortened circadian period length. At a mechanistic level some CAMKs undergo more auto-phosphorylations in Δ nca-2 , consistent with high calcium in the Δ nca-2 mutant influencing the enzymatic activity of CAMKs. NCA-2 interacts with multiple proteins including CSP-6, a protein known to be required for circadian output. Most importantly, expression of nca- 2 is circadian clock-controlled at both the transcriptional and translational levels, and this in combination with the period effects seen in strains lacking NCA-2, firmly places calcium signaling within the larger circadian system where it acts as both an input to and output from the core clock. Importance Circadian rhythms are based on cell-autonomous, auto-regulatory, feedback loops formed by interlocked positive and negative arms, and they regulate myriad molecular and cellular processes in most eukaryotes including fungi. Intracellular calcium signaling is also a process that impacts a broad range of biological events in most eukaryotes. Clues have suggested that calcium signaling can influence circadian oscillators through multiple pathways; however, mechanistic details have been lacking in microorganisms. Building on prior work describing calcium transporters in the fungus Neurospora , one such transporter, NCA-2, was identified as a regulator of circadian period length. Increased intracellular calcium levels caused by loss of NCA-2 results in over-activation of calcium-responsive protein kinases, in turn leading to a shortened circadian period length. Importantly, expression of NCA-2 is itself controlled by the molecular clock. In this way calcium signaling can be seen as providing both input to and output from the circadian system.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2021,"id":224523,"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":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9605,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":486296,"name":"Xiaoying Zhou","orcid":"0000-0003-3298-5089","position":1,"is_corresponding":false},{"id":393304,"name":"Scott A. Gerber","orcid":"0000-0002-2964-5051","position":2,"is_corresponding":false},{"id":61810,"name":"Jennifer Loros","orcid":"0000-0003-0451-2858","position":3,"is_corresponding":false},{"id":61811,"name":"Jay Dunlap","orcid":"0000-0003-1577-0457","position":4,"is_corresponding":false},{"id":826569,"name":"Bin Wang","orcid":"0000-0002-0068-2887","position":0,"is_corresponding":true}],"reference_count":97,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-18T23:54:18.470602Z","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":[]}