calcium channels

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1、CalciumChannelsCalciumChannelVoltage-dependentcalciumchannels(VDCC)areagroupofvoltage-gatedionchannelsfoundinexcitablecellswithapermeabilitytotheionCa2+.Activatedbychangesinmembranepotential.Ligand-gatedcalciumchannels(LGCC)areagroupoftransmembraneionchannelsthatareopened

2、orclosedinresponsetothebindingofachemicalmessenger,suchasaneurotransmitter.ActivatedbychangeinchemicalpotentialTypeofVDCCStuctureofVDCCVDCCareformedasacomplexofseveralsubunits:α1,α2δ,β,γ.α1hasfourrepeatsofthesixtransmembrane(S1–S6)spanningdomain.Theporeregionisformedbyahy

3、drophilicregionbetweenS5andS6.TheS4domainhaspositivelychargedresidues(lysine/arginine)thatfunctionasthevoltagesensorofthechannel.KeyregionsofCaVchannelregulationincludebindingregionsintheC-terminusforCa2+(EFhand)andcalmodulin(CaM)(IQdomain)inmost,butnotallCaVα1subunits.St

4、ructure-Functionrelationshipinvoltage-gatedchannelLigand-gatedcalciumchannelsCalciumionmaytriggeramusclecontraction,secretionbyexocytosisorchangetheactivityofintracellularproteins.Inthelastcase,calciumionactsasasecondarymessenger.Calciumdoesthisbyfirstbindingwithacytosoli

5、cproteincalledcalmodulin.Thecalcium-calmodulincomplexusuallyactivatesaproteinkinasethataffectsproteinactivitybyphosphorylation.CalciumChannelsBlocker