SPLUNC1 is a negative regulator of the Orai1 Ca2+ channel

dc.contributor.authorWu, Tongdeen
dc.contributor.authorGoriounova, Alexandra S.en
dc.contributor.authorWorthington, Erin N.en
dc.contributor.authorWrennall, Joe A.en
dc.contributor.authorGhosh, Arunavaen
dc.contributor.authorAhmad, Sairaen
dc.contributor.authorSassano, M. Florien
dc.contributor.authorTarran, Roberten
dc.date.accessioned2022-06-28T15:16:12Zen
dc.date.available2022-06-28T15:16:12Zen
dc.date.issued2022-05en
dc.description.abstractOrai1 is a ubiquitously-expressed plasma membrane Ca2+ channel that is involved in store-operated Ca2+ entry (SOCE): a fundamental biological process that regulates gene expression, the onset of inflammation, secretion, and the contraction of airway smooth muscle (ASM). During SOCE, Ca2+ leaves the endoplasmic reticulum, which then stimulates a second, amplifying wave of Ca2+ influx through Orai1 into the cytoplasm. Short Palate LUng and Nasal epithelial Clone 1 (SPLUNC1; gene name BPIFA1) is a multi-functional, innate defense protein that is highly abundant in the lung. We have previously reported that SPLUNC1 was secreted from epithelia, where it bound to and inhibited Orai1, leading to reduced SOCE and ASM relaxation. However, the underlying mechanism of action is unknown. Here, we probed the SPLUNC1-Orai1 interactions in ASM and HEK293T cells using biochemical and imaging techniques. We observed that SPLUNC1 caused a conformational change in Orai1, as measured using Forster resonance energy transfer (FRET). SPLUNC1 binding also led to Nedd4-2 dependent ubiquitination of Orai1. Moreover, SPLUNC1 internalized Orai1 to lysosomes, leading to Orai1 degradation. Thus, we conclude that SPLUNC1 is an allosteric regulator of Orai1. Our data indicate that SPLUNC1-mediated Orai1 inhibition could be utilized as a therapeutic strategy to reduce SOCE.en
dc.description.notesWe thank Dr. Donald Gill, Dr. Peter Snyder, Dr. Jim Putney, and Dr. Colin Bingle for generously donating DNA constructs. Human ASM cells were generously provided by Dr. Raymond Penn at Thomas Jefferson University. This work was funded by the American Asthma Foundation and NIH Grants HL108927, ES025198, DK065988.en
dc.description.sponsorshipAmerican Asthma Foundation; NIH [HL108927, ES025198, DK065988]en
dc.description.versionPublished versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.14814/phy2.15306en
dc.identifier.issn2051-817Xen
dc.identifier.issue10en
dc.identifier.othere15306en
dc.identifier.pmid35581745en
dc.identifier.urihttp://hdl.handle.net/10919/110956en
dc.identifier.volume10en
dc.language.isoenen
dc.publisherWileyen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjectairwayen
dc.subjectairway smooth muscleen
dc.subjectBPIFA1en
dc.subjectcalciumen
dc.subjectFRETen
dc.subjectNEDD4-2en
dc.titleSPLUNC1 is a negative regulator of the Orai1 Ca2+ channelen
dc.title.serialPhysiological Reportsen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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