B cell receptor‐induced Ca2+ mobilization mediates F‐actin rearrangements and is indispensable for adhesion and spreading of B lymphocytes

[摘要] Bcellsacquiremembrane‐boundcognateantigensfromthesurfaceoftheAPCsbyforminganIS,similartothatseeninTcells.Recognitionofmembrane‐boundantigensontheAPCsinitiatesadhesionofBlymphocytestotheantigen‐tetheredsurface,whichisfollowedbytheformationofradiallamellipodia‐likestructures,aprocessknownasBcellspreading.ThespreadingresponserequirestherearrangementofthesubmembraneactincytoskeletonandisregulatedmainlyviasignalstransmittedbytheBCR.Here,weshowthatcytoplasmiccalciumisaregulatorofactincytoskeletondynamicsinBlymphocytes.WefindthatBCR‐inducedcalciummobilizationisindispensibleforadhesionandspreadingofBcellsandthatPLCγandCRAC‐mediatedcalciummobilizationarecriticalregulatorsoftheseprocesses.Measuringcalciumandactindynamicsinlivecells,wefoundthatagenerationofactin‐basedmembraneprotrusionisstronglylinkedtothedynamicsofacytoplasmic‐freecalciumlevel.Finally,wedemonstratethatPLCγandCRACchannelsregulatetheactivityofactin‐severingproteincofilin,linkingBCR‐inducedcalciumsignalingtotheactindynamics...

[学科分类] 生理学

[关键词] B cell spreading;membrane‐bound antigens;B cell activation;Ca2+ signal;cofilin