Biogenesis of secretory organelles during B cell differentiation

Journal of Leukocyte Biology: An Official Publication of the Reticuloendothelial Society

关键词: endoplasmic reticulum;    Golgi apparatus;    immunoglobulin secretion;    plasma cell;    microscopy;   

DOI  :  10.1189/jlb.1208774

学科分类：生理学

来源: Federation of American Societies for Experimental Biology

【 摘 要 】

ThedifferentiationofBcellsintoIg‐secretingplasmacellsrequirestheexpansionofsecretoryorganellestocopewiththeincreasedcargoload.Toevaluatethetimelineofthisprocess,wehavequantitatedthekineticsofsecretoryorganelleexpansionrelativetoIgsecretionandexaminedregulatorycomponentsofsecretorytransportfollowinginvitroactivationofhumanBlymphocytes.UnstimulatedBcellscontainminimalendomembranes.Afteractivation,ERmembraneinductionappearsastightlypackedsphericalstructuresof0.5–1μmdiameterconcentratedinajuxtanuclearposition.Whenthecellsdifferentiateintoplasmablasts,thereisdramaticcell‐sizeincrease,buttheERremainsconcentratedclosetothenucleusandonlylaterfillstheentirecell.Insharpcontrast,previousstudiesinothercelltypeshavefoundthattheERexpandsinsynchronywithincreasingcellsizeduringinterphase,byextensionofERtubulesunderthePM.Inthisstudy,theGolgiremainsconsistentlyasasinglejuxtanuclearstructurebutlinearlyexpandssixfoldinvolumeduringBcellactivation.Furthermore,followingactivecellproliferation,ERexitsitesproliferaterapidly,increasingalmostfourfoldinnumber,inparallelwithasharpincreaseinIgsecretion.ThesefindingsdemonstratethatthecontroloforganellebiogenesisandexpansioninprimaryhumanBcellsaredifferentiallyregulatedbycargofluxcausedbyIgsynthesis...

【 授权许可】

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