Proteins containing an Rho GTPase-activating protein （RhoGAP） domain work as molecular switches involved in the regulation of diverse cellular functions. The ability of these GTPases to regulate a wide number of cel...Proteins containing an Rho GTPase-activating protein （RhoGAP） domain work as molecular switches involved in the regulation of diverse cellular functions. The ability of these GTPases to regulate a wide number of cellular processes comes from their interactions with multiple effectors and inhibitors, including the RhoGAP family, which stimulates their intrinsic GTPase activity. Here, a phylogenetic approach was applied to study the evolutionary relationship among 59 RhoGAP domain-containing proteins. The sequences were aligned by their RhoGAP domains and the phylogenetic hypotheses were generated using Maximum Parsimony and Bayesian analyses. The character tracing of two traits, GTPase activity and presence of other domains, indicated a significant phylogenetic signal for both of them.展开更多
Rho GTPases are molecular switches that act as key regulators of a many cellular processes, including cell movement, morphogenesis, host defense, cell division and gene expression. Rho GTPases are found in all eukaryo...Rho GTPases are molecular switches that act as key regulators of a many cellular processes, including cell movement, morphogenesis, host defense, cell division and gene expression. Rho GTPases are found in all eukaryotic kingdoms. Plants lack clear homologs to conventional Rho GTPases found in yeast and animals; instead, they have over time developed a unique subfamily, ROPs, also known as RAC. The origin of ROP-like proteins appears to precede the appearance of land plants. This review aims to discuss the evolution of ROP/RAC and to compare plant ROP and animal Rho GTPases, focusing on similarities and differences in regulation of the GTPases and their downstream effectors.展开更多
ROP GTPases regulate various cellular processes,including plant immunity.While ROP GTPase activation has been reported during plant immune responses,the mechanisms underlying the dynamic deactivation of ROP GTPases re...ROP GTPases regulate various cellular processes,including plant immunity.While ROP GTPase activation has been reported during plant immune responses,the mechanisms underlying the dynamic deactivation of ROP GTPases remain unclear.In this study,we identified the autophagy kinase OsATG1 as a key regu-lator that interacts with and phosphorylates SPIN6,a plant-specific ROP GTPase-activating protein(Rho-GAP),which in turn deactivates the ROP GTPase OsRac1.OsATG1-mediated multi-sitephosphorylation is necessaryfor theGAPactivityof SPIN6tohydrolyzeOsRac1-GTP,andoverexpressionofaphosphomimic form of SPIN6attenuates rice immunity.Weshowedthat two isoformsofOsATG1,OsATG1a andOsATG1b,operate redundantly in rice immunity to the fungal pathogen Magnaporthe oryzae.Double mutants of OsATG1a and OsATG1b exhibit stronger resistance as well as developmental defects and complete steril-ity.Moreover,OsATG1 interacts with OsATG8.Phenotypic analyses of OsATG8 transgenic plants reveal that OsATG8 positively regulates rice immunity,but OsATG8 activates immunity partially indepen-dent of its function in autophagy,because overexpressing the lipidation-defective OsATGg^(G117A) or accu-mulating non-lipidated OsATG8 in the osatg7 mutant enhances rice disease resistance.Mechanistically,OsATG8 promotes OsATG1 turnover,whereas OsATG8^(G117A) is sufficient to deplete OsATG1,leading to SPiN6 dissociation and degradation.As autophagy is essential in nutrient recycling,we found that nutrient limitations induce OsATG8 expression and rice immunity while suppressing SPIN6.However,SPIN6 phos-phorylation inhibits this nutrient-limitation-induced immunity.Taken together,our results suggest that OsATG1 and OsATG8 possess autophagy-independent functions to transform nutrient limitation into immunityviaplant-specific ROP GTPase signaling.展开更多
文摘Proteins containing an Rho GTPase-activating protein （RhoGAP） domain work as molecular switches involved in the regulation of diverse cellular functions. The ability of these GTPases to regulate a wide number of cellular processes comes from their interactions with multiple effectors and inhibitors, including the RhoGAP family, which stimulates their intrinsic GTPase activity. Here, a phylogenetic approach was applied to study the evolutionary relationship among 59 RhoGAP domain-containing proteins. The sequences were aligned by their RhoGAP domains and the phylogenetic hypotheses were generated using Maximum Parsimony and Bayesian analyses. The character tracing of two traits, GTPase activity and presence of other domains, indicated a significant phylogenetic signal for both of them.
基金This work was supported by the Bioteclmology and Functional genomics(FUGE)programs of the Norwegian Research Council through grants NFR 159959,164583 and 151991(T B,P W and A M B)by grants from the National Science Foundation,the Department of Energy and the US Department of Agriculture(Z Y).
文摘Rho GTPases are molecular switches that act as key regulators of a many cellular processes, including cell movement, morphogenesis, host defense, cell division and gene expression. Rho GTPases are found in all eukaryotic kingdoms. Plants lack clear homologs to conventional Rho GTPases found in yeast and animals; instead, they have over time developed a unique subfamily, ROPs, also known as RAC. The origin of ROP-like proteins appears to precede the appearance of land plants. This review aims to discuss the evolution of ROP/RAC and to compare plant ROP and animal Rho GTPases, focusing on similarities and differences in regulation of the GTPases and their downstream effectors.
基金supported by grants from the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSCB-202301)the National Natural Science Foundation of China(32161143009,31972225,and 32272505)to Y.N.+1 种基金the National Natural Science Foundation of China(U24A20388)to R.W.the China Postdoctoral Science Foundation(2021M693457)to F.H.
文摘ROP GTPases regulate various cellular processes,including plant immunity.While ROP GTPase activation has been reported during plant immune responses,the mechanisms underlying the dynamic deactivation of ROP GTPases remain unclear.In this study,we identified the autophagy kinase OsATG1 as a key regu-lator that interacts with and phosphorylates SPIN6,a plant-specific ROP GTPase-activating protein(Rho-GAP),which in turn deactivates the ROP GTPase OsRac1.OsATG1-mediated multi-sitephosphorylation is necessaryfor theGAPactivityof SPIN6tohydrolyzeOsRac1-GTP,andoverexpressionofaphosphomimic form of SPIN6attenuates rice immunity.Weshowedthat two isoformsofOsATG1,OsATG1a andOsATG1b,operate redundantly in rice immunity to the fungal pathogen Magnaporthe oryzae.Double mutants of OsATG1a and OsATG1b exhibit stronger resistance as well as developmental defects and complete steril-ity.Moreover,OsATG1 interacts with OsATG8.Phenotypic analyses of OsATG8 transgenic plants reveal that OsATG8 positively regulates rice immunity,but OsATG8 activates immunity partially indepen-dent of its function in autophagy,because overexpressing the lipidation-defective OsATGg^(G117A) or accu-mulating non-lipidated OsATG8 in the osatg7 mutant enhances rice disease resistance.Mechanistically,OsATG8 promotes OsATG1 turnover,whereas OsATG8^(G117A) is sufficient to deplete OsATG1,leading to SPiN6 dissociation and degradation.As autophagy is essential in nutrient recycling,we found that nutrient limitations induce OsATG8 expression and rice immunity while suppressing SPIN6.However,SPIN6 phos-phorylation inhibits this nutrient-limitation-induced immunity.Taken together,our results suggest that OsATG1 and OsATG8 possess autophagy-independent functions to transform nutrient limitation into immunityviaplant-specific ROP GTPase signaling.
