Post-translational modifications play essential roles in finely modulating eukaryotic circadian clock systems.In plants,the effects of O-glycosylation on the circadian clock and the underlying mechanisms remain largel...Post-translational modifications play essential roles in finely modulating eukaryotic circadian clock systems.In plants,the effects of O-glycosylation on the circadian clock and the underlying mechanisms remain largely unknown.The O-fucosyltransferase SPINDLY(SPY)and the O-GIcNAc transferase SECRET AGENT(SEC)are two prominent O-glycosylation enzymes in higher plants,with both overlapped and unique functions in plant growth and development.Unlike the critical role of O-GIcNAc in regulating the animal circadian clock,here we report that nuclear-localized SPY,but not SEC,specifically modulates the pace of the Arabidopsis circadian clock.By identifying the interactome of SPY,we identified PSEUDORESPONSE REGULATOR 5(PRR5),one of the core circadian clock components,as a new SPY-interacting protein.PRR5 can be O-fucosylated by SPY in pianta,while point mutation in the catalytic domain of SPY abolishes the O-fucosylation of PRR5.The protein abundance of PRR5 is strongly increased in spy mutants,while the degradation rate of PRR5 is much reduced,suggesting that PRR5 proteolysis is promoted by SPY-mediated O-fucosylation.Moreover,multiple lines of genetic evidence indicate that PRR5 is a major downstream target of SPY to specifically mediate its modulation of the circadian clock.Collectively,our findings provide novel insights into the specific role of the O-fucosyltransferase activity of SPY in modulating the circadian clock and implicate that O-glycosylation might play an evolutionarily conserved role in modulating the circadian clock system,via O-GIcNAcylation in mammals,but via O-fuco-sylation in higher plants.展开更多
基金suppoded by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB27030206)National Natural Science Foundation of China(No.31770287)+1 种基金National Key Research and Development Program of China(2016YFD0100600)to L.W.the National Institutes of Health(R01 GM100051)to T.P.S.
文摘Post-translational modifications play essential roles in finely modulating eukaryotic circadian clock systems.In plants,the effects of O-glycosylation on the circadian clock and the underlying mechanisms remain largely unknown.The O-fucosyltransferase SPINDLY(SPY)and the O-GIcNAc transferase SECRET AGENT(SEC)are two prominent O-glycosylation enzymes in higher plants,with both overlapped and unique functions in plant growth and development.Unlike the critical role of O-GIcNAc in regulating the animal circadian clock,here we report that nuclear-localized SPY,but not SEC,specifically modulates the pace of the Arabidopsis circadian clock.By identifying the interactome of SPY,we identified PSEUDORESPONSE REGULATOR 5(PRR5),one of the core circadian clock components,as a new SPY-interacting protein.PRR5 can be O-fucosylated by SPY in pianta,while point mutation in the catalytic domain of SPY abolishes the O-fucosylation of PRR5.The protein abundance of PRR5 is strongly increased in spy mutants,while the degradation rate of PRR5 is much reduced,suggesting that PRR5 proteolysis is promoted by SPY-mediated O-fucosylation.Moreover,multiple lines of genetic evidence indicate that PRR5 is a major downstream target of SPY to specifically mediate its modulation of the circadian clock.Collectively,our findings provide novel insights into the specific role of the O-fucosyltransferase activity of SPY in modulating the circadian clock and implicate that O-glycosylation might play an evolutionarily conserved role in modulating the circadian clock system,via O-GIcNAcylation in mammals,but via O-fuco-sylation in higher plants.
