{"doi":"10.1101/2021.08.30.458203","title":"Loss of Secretory Pathway Ca <sup>2+</sup> ATPase (SPCA1) Impairs Insulin Secretion and Reduces Autophagy in the Pancreatic Islet","abstract":"Abstract The β cell Golgi apparatus serves as a significant store of intracellular Ca 2+ and an important site of proinsulin maturation. However, the contribution of Golgi Ca 2+ to diabetes pathophysiology is unknown. The Golgi primarily utilizes the Secretory Pathway Ca 2+ ATPase (SPCA1) to maintain intraluminal Ca 2+ stores, and loss of SPCA1 has been linked to impaired Golgi function in other cell types. Here, we demonstrated that SPCA1 expression is decreased in islets from diabetic mice and human organ donors with type 2 diabetes, suggesting SPCA1 may impact diabetes development. INS-1 β cells lacking SPCA1 (SPCA1KO) showed reduced intraluminal Golgi Ca 2+ levels, reduced glucose-stimulated insulin secretion (GSIS), and increased insulin content. Islets from SPCA1 haploinsufficient mice (SPCA1 +/- ) exhibited reduced GSIS, altered glucose-induced Ca 2+ oscillations, and altered insulin granule maturation. Autophagy can regulate granule homeostasis, therefore we induced autophagy with Torin1 and found that SPCA1KO cells and SPCA1 +/- islets had reduced levels of the autophagosome marker LC3-II. Furthermore, SPCA1KO LC3-II were unchanged after blocking autophagy initiation or autophagolysosome fusion and acidification. Thus, we concluded that β cell SPCA1 plays an important role in the maintenance of Golgi Ca 2+ homeostasis and reduced Golgi Ca 2+ impairs autophagy initiation and may impact insulin granule homeostasis.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2021,"id":221599,"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":0.9531,"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":461847,"name":"Xin Tong","orcid":"0000-0003-4408-3832","position":1,"is_corresponding":false},{"id":461851,"name":"Staci A. Weaver","orcid":"0000-0002-2974-2580","position":2,"is_corresponding":false},{"id":563213,"name":"Charanya Muralidharan","orcid":"0000-0002-4909-7056","position":3,"is_corresponding":false},{"id":821709,"name":"Preethi Krishnan","orcid":"0000-0002-3786-5732","position":4,"is_corresponding":false},{"id":461853,"name":"Tatsuyoshi Kono","orcid":"0000-0002-7524-6836","position":5,"is_corresponding":false},{"id":7388,"name":"Carmella Evans‐Molina","orcid":"0000-0001-7764-8663","position":6,"is_corresponding":false},{"id":332522,"name":"Robert N. Bone","orcid":"0000-0003-3222-8918","position":0,"is_corresponding":true}],"reference_count":61,"raw_metadata":null,"created_at":"2026-07-18T23:53:55.215284Z","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":[]}