简介：Insulinsecretorygranules(ISGs),agroupofdistinguishingorganellesinpancreaticβcells,areresponsibleforthestorageandsecretionofinsulintomaintainbloodglucosehomeostasis.ThemolecularmechanismsofISGbiogenesis,maturation,transportation,andexocytosisarestilllargelyunknownbecausetheproteinsinvolvedinthesedistinctstepshavenotbeenfullyidentified.Subcellularfractionationbydensitygradientcentrifugationhasbeensuccessfullyemployedtoanalyzetheproteomesofnumerousorganelles.However,useofthismethodtoelucidatetheISGproteomeislimitedbyco-fractionatedcontaminantsbecause1SGsareverydynamicandhaveabundantexchangesorcontactswithotherorganelles,suchastheGolgiapparatus,lysosomes,andendosomes.Inthisstudy,wedevelopedanewstrategyforidentifyingISGproteinsbyproteincorrelationprofiling(PCP)-basedproteomics,whichincludedISGpurificationbyOptiPrepdensitygradientcentrifugation,label-freequantitativeproteome,andidentificationofISGproteinsbycorrelatingfractionationprofilesbetweencandidatesandknownISGmarkers.Usingthisapproach,wewereabletoidentify81ISGproteins.Amongthem,TM9SF3,anine-transmembraneprotein,wasconsideredahighconfidenceISGcandidateproteinhighlightedinthePCPnetwork.FurtherbiochemicalandimmunofluorescenceassaysindicatedthatTMgSF3localizedinISGs,suggestingthatitisapotentialnewISGmarker.