Perception of the phytohormone ethylene is accomplished by a small family of integral membrane receptors. In Arabidopsis, five ethylene receptor proteins are known, including ethylene resistant I （ETR1）. The hydroph...Perception of the phytohormone ethylene is accomplished by a small family of integral membrane receptors. In Arabidopsis, five ethylene receptor proteins are known, including ethylene resistant I （ETR1）. The hydrophobic aminoterminal domain of these receptors contains the ethylene-binding site while the carboxyl-terminal part consists of a histidine kinase domain and a response regulator domain, which are well known elements found in bacterial two-component signaling. The soluble membrane-extrinsic carboxyl-terminal part of the receptor, which is likely to play an important role in signal transduction, showed intrinsic kinase activity when expressed and purified on its own. However, a correlation between signal input and autokinase activity was not established in these studies, as receptors were missing the trans- membrane amino-terminal sensor domain. Thus, it is still unclear whether autophosphorylation occurs in response to perception of the ethylene signal. Here, we report on autophosphorylation studies of purified full-length ETR1. Autoki- nase activity of the purified receptor is controlled by ethylene or by ethylene agonists like the π-acceptor compound cyanide. In fact, both signal molecules were able to completely turn off the intrinsic kinase activity, Furthermore, the observed inhibition of autophosphorylation in ETR1 by both molecules could be prevented when the ethylene antagonist 1-methyl-cyclopropene （MOP） was applied.展开更多
Plant intracellular nucleotide-binding domain leucine-rich repeat(NLR)receptors play crucial roles in immune responses against pathogens.How diverse NLRs recognize different pathogen effectors remains a significant qu...Plant intracellular nucleotide-binding domain leucine-rich repeat(NLR)receptors play crucial roles in immune responses against pathogens.How diverse NLRs recognize different pathogen effectors remains a significant ques-tion.A recent study published in Nature uncovered how pepper NLR Tsw detects phytohormone receptors’interfer-ence caused by tomato spotted wilt virus(TSWV)effector,triggering a robust immune response,showcasing a new manner of NLR guarding.展开更多
文摘Perception of the phytohormone ethylene is accomplished by a small family of integral membrane receptors. In Arabidopsis, five ethylene receptor proteins are known, including ethylene resistant I （ETR1）. The hydrophobic aminoterminal domain of these receptors contains the ethylene-binding site while the carboxyl-terminal part consists of a histidine kinase domain and a response regulator domain, which are well known elements found in bacterial two-component signaling. The soluble membrane-extrinsic carboxyl-terminal part of the receptor, which is likely to play an important role in signal transduction, showed intrinsic kinase activity when expressed and purified on its own. However, a correlation between signal input and autokinase activity was not established in these studies, as receptors were missing the trans- membrane amino-terminal sensor domain. Thus, it is still unclear whether autophosphorylation occurs in response to perception of the ethylene signal. Here, we report on autophosphorylation studies of purified full-length ETR1. Autoki- nase activity of the purified receptor is controlled by ethylene or by ethylene agonists like the π-acceptor compound cyanide. In fact, both signal molecules were able to completely turn off the intrinsic kinase activity, Furthermore, the observed inhibition of autophosphorylation in ETR1 by both molecules could be prevented when the ethylene antagonist 1-methyl-cyclopropene （MOP） was applied.
基金The Natural Sciences and Engineering Research Council of Canada(NSERC)-Discovery and NSERC-CREATE PRoTECT programs provide us with financial supportsupported by scholarships from MSL Graduate Student Award and China Scholarship Council.
文摘Plant intracellular nucleotide-binding domain leucine-rich repeat(NLR)receptors play crucial roles in immune responses against pathogens.How diverse NLRs recognize different pathogen effectors remains a significant ques-tion.A recent study published in Nature uncovered how pepper NLR Tsw detects phytohormone receptors’interfer-ence caused by tomato spotted wilt virus(TSWV)effector,triggering a robust immune response,showcasing a new manner of NLR guarding.
