{"doi":"10.1111/tra.12736","title":"Phosphatidylinositol 3, <scp>5‐bisphosphate</scp> regulates Ca <sup>2+</sup> transport during yeast vacuolar fusion through the Ca <sup>2+</sup> <scp>ATPase Pmc1</scp>","abstract":"Abstract The transport of Ca 2+ across membranes precedes the fusion and fission of various lipid bilayers. Yeast vacuoles under hyperosmotic stress become fragmented through fission events that requires the release of Ca 2+ stores through the TRP channel Yvc1. This requires the phosphorylation of phosphatidylinositol‐3‐phosphate (PI3P) by the PI3P‐5‐kinase Fab1 to produce transient PI(3,5)P 2 pools. Ca 2+ is also released during vacuole fusion upon trans‐ SNARE complex assembly, however, its role remains unclear. The effect of PI(3,5)P 2 on Ca 2+ flux during fusion was independent of Yvc1. Here, we show that while low levels of PI(3,5)P 2 were required for Ca 2+ uptake into the vacuole, increased concentrations abolished Ca 2+ efflux. This was as shown by the addition of exogenous dioctanoyl PI(3,5)P 2 or increased endogenous production of by the hyperactive fab1 T2250A mutant. In contrast, the lack of PI(3,5)P 2 on vacuoles from the kinase dead fab1 EEE mutant showed delayed and decreased Ca 2+ uptake. The effects of PI(3,5)P 2 were linked to the Ca 2+ pump Pmc1, as its deletion rendered vacuoles resistant to the effects of excess PI(3,5)P 2 . Experiments with Verapamil inhibited Ca 2+ uptake when added at the start of the assay, while adding it after Ca 2+ had been taken up resulted in the rapid expulsion of Ca 2+ . Vacuoles lacking both Pmc1 and the H + /Ca 2+ exchanger Vcx1 lacked the ability to take up Ca 2+ and instead expelled it upon the addition of ATP. Together these data suggest that a balance of efflux and uptake compete during the fusion pathway and that the levels of PI(3,5)P 2 can modulate which path predominates.","journal":"Traffic","year":2020,"id":69731,"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":20,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.952,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":369254,"name":"Katherine D. Sullivan","orcid":"0000-0002-4898-5641","position":1,"is_corresponding":false},{"id":369255,"name":"Chi Zhang","orcid":"0000-0002-7735-5614","position":2,"is_corresponding":false},{"id":369256,"name":"David A. Rivera‐Kohr","orcid":"0000-0001-7199-3490","position":3,"is_corresponding":false},{"id":369257,"name":"Annie Guo","orcid":"0000-0003-4635-1183","position":4,"is_corresponding":false},{"id":370374,"name":"Logan R. Hurst","orcid":null,"position":5,"is_corresponding":false},{"id":370375,"name":"Ez C. Ellis","orcid":null,"position":6,"is_corresponding":false},{"id":370376,"name":"Matthew L. Starr","orcid":null,"position":7,"is_corresponding":false},{"id":369258,"name":"Brandon C. Jones","orcid":"0000-0002-9352-5521","position":8,"is_corresponding":false},{"id":369259,"name":"Rutilio A. Fratti","orcid":"0000-0001-9109-6666","position":9,"is_corresponding":false},{"id":369253,"name":"Gregory E. Miner","orcid":"0000-0002-1124-4217","position":0,"is_corresponding":true}],"reference_count":64,"raw_metadata":null,"created_at":"2026-07-18T21:42:48.813846Z","pmid":"32388897","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":[]}