{"doi":"10.1101/2020.09.25.313916","title":"Mg <sup>2+</sup> -binding shifts the IM30 activity from membrane protection to membrane destabilization","abstract":"ABSTRACT The inner membrane-associated protein of 30 kDa (IM30) is essential in chloroplasts and cyanobacteria. The spatio-temporal cellular localization of the protein appears to be highly dynamic and triggered by internal as well as external stimuli, mainly light intensity. A soluble fraction of the protein is localized in the cyanobacterial cytoplasm or the chloroplast stroma, respectively. Additionally, the protein attaches to the thylakoid membrane as well as to the chloroplast inner envelope or the cyanobacterial cytoplasmic membrane, respectively, especially under conditions of membrane stress. IM30 is involved in thylakoid membrane biogenesis and/or maintenance, where it either stabilizes membranes and/or triggers membrane-fusion processes. These apparently contradicting processes have to be tightly controlled and separated spatiotemporally in chloroplasts and cyanobacteria. The latter process depends on Mg 2+ -binding to IM30; yet, it still is unclear how Mg 2+ -loaded IM30 interacts with membranes and promotes membrane fusion. Here we show that interaction of Mg 2+ with IM30 results in increased binding of IM30 to native as well as model membranes. Via Atomic Force Microscopy in liquid, IM30-induced bilayer defects were observed in solid-supported bilayers in presence of Mg 2+ . The observed interaction of IM30 with membrane surfaces differs dramatically from previously observed membrane-stabilizing, carpet-like structures in the absence of Mg 2+ . Mg 2+ -induced alterations of the IM30 structure switches the IM30 activity from a membrane-stabilizing to a membrane-destabilizing function, a crucial step in membrane fusion.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2020,"id":131084,"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":0.9507,"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":472779,"name":"Amelie Axt","orcid":"0000-0002-5313-9319","position":1,"is_corresponding":false},{"id":474039,"name":"Carmen Siebenaller","orcid":null,"position":2,"is_corresponding":false},{"id":585034,"name":"Hilal Sonel","orcid":null,"position":3,"is_corresponding":false},{"id":472783,"name":"Nadja Hellmann","orcid":"0000-0002-6591-8926","position":4,"is_corresponding":false},{"id":472785,"name":"Stefan A. L. Weber","orcid":"0000-0003-3052-326X","position":5,"is_corresponding":false},{"id":472786,"name":"Dirk Schneider","orcid":"0000-0003-4517-6387","position":6,"is_corresponding":false},{"id":472777,"name":"Benedikt Junglas","orcid":"0000-0001-9348-3379","position":0,"is_corresponding":true}],"reference_count":53,"raw_metadata":null,"created_at":"2026-07-18T23:16:00.235845Z","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":[]}