简介:Humanrhodopsinkinase(RK)andacarboxylterminus-truncatedmutantRKlackingthelast59aminoacids(RKC)wereexpressedinhumanembryonickidney293cellstoinvestigatetheroleofthecarboxylterminusofRKinrecognitionandphosphorylationofrhodopsin.RKC,likethewild-typeRK,wasdetectedinbothplasmamembranesandcytosolicfractions.TheCterminaltruncatedrhodopsinkinasewasunabletophosphorylatephoto-activatedrhodopsin,butpossesseskinaseactivitysimilartothewild-typeRKinphosphorylationofsmallpeptidesubstrate.ItsuggeststhatthetruncationdidnotdisturbthegrossstructuresofRKcatalyticdomain.OurresultsalsoshowthatRKCfailedtotranslocatetophoto-activatedrodoutsegments.Takentogether,ourstudydemonstratethecarboxylterminusofRKisrequiredforphosphorylationofphoto-activatedrhodopsinandstronglyindicatethatcarboxyl-terminusofRKmaybeinvolvedininteractionwithphoto-activatedrhodopsin.