Auxin regulates plant growth by integrating transport and signaling.Polar auxin transport establishes auxin gradients essential for development,with PIN-FORMED(PIN)efflux carriers generating directionality and AUXIN1/...Auxin regulates plant growth by integrating transport and signaling.Polar auxin transport establishes auxin gradients essential for development,with PIN-FORMED(PIN)efflux carriers generating directionality and AUXIN1/LIKE-AUX1(AUX1/LAX)influx carriers ensuring efficient uptake.Canonical signaling begins when auxin binds TRANSPORT INHIBITOR RESPONSE 1/AUXIN SIGNALING F-BOX PROTEIN(TIR1/AFB)receptors,the F-box component of the SKP1-CULLIN1-F-box(SCF)E3 ubiquitin ligase complex(Gray et al.,2001).Auxin promotes recruitment and degradation of AUXIN/INDOLE-3-ACETIC ACID(AUX/IAA)repressors,thereby releasing AUXIN RESPONSE FACTOR(ARF)to activate transcription(Gray et al.,2001).Recent discoveries have expended this model.Cryo-electron microscopy(cryo-EM)structures of AUX1 clarified its proton(H+)-coupled import(Yang et al.,2025),and TIR1 was shown to function as an adenylate cyclase(AC),producing c AMP to activate transcription(Chen et al.,2025).Synthetic promoter studies further revealed a bi-layer ARF/cis-element code shaping cel type-specific gene expression(Martin-Arevalil o et al.,2025).展开更多
MAP kinase-interacting kinase-2(Mnk2)is one of the downstream kinasesactivated by MAP kinases.It phosphorylates the eukaryotic initiation factor 4E(elF4E),althoughthe role of elF4E phosphorylation and the role of Mnk2...MAP kinase-interacting kinase-2(Mnk2)is one of the downstream kinasesactivated by MAP kinases.It phosphorylates the eukaryotic initiation factor 4E(elF4E),althoughthe role of elF4E phosphorylation and the role of Mnk2 in the process of proteintranslation are notwell understood.Except for elF4E,other physiological substrates of Mnk2 are still unidentified.Tolook for these unidentified substrates and to reveal the physiological function of Mnk2,weperformed a yeast two-hybrid screening with Mnk2 as the bait.The results demonstrated Mnk2 couldinteract with VHL(von Hippel-Lindau tumor suppressor),Rbx1(ring-box1)and Cul2(Cullin2)proteinsin yeast cells.Furthermore,we validated the interaction between Mnk2 and VHL proteins inmammalian cells by co-immunoprecipitation analysis.Because the three proteins VHL,Rbx1 and Cul2are all components of the CBC^(VHL)ubiquitin ligase E3 complex,it has been shown that Mnk2 caninteract with CBC^(VHL)complex,and is probably one of the newsubstrates of the CBC^(VHL)complex.Furthermore,during the interaction of Mnk2 with von Hippel-Lindau(VHL)tumor suppressor-bindingprotein 1(VBP1),it appears that Mnk2 also joins to modulate cell shape as VBP1 plays an importantrole in the process of the maturation of the cytoskeleton and in the process of morphogenesis.展开更多
基金Young Scientists Fund of the National Natural Science Foundation of China(61572004,L.L.,32202496,H.H.)。
文摘Auxin regulates plant growth by integrating transport and signaling.Polar auxin transport establishes auxin gradients essential for development,with PIN-FORMED(PIN)efflux carriers generating directionality and AUXIN1/LIKE-AUX1(AUX1/LAX)influx carriers ensuring efficient uptake.Canonical signaling begins when auxin binds TRANSPORT INHIBITOR RESPONSE 1/AUXIN SIGNALING F-BOX PROTEIN(TIR1/AFB)receptors,the F-box component of the SKP1-CULLIN1-F-box(SCF)E3 ubiquitin ligase complex(Gray et al.,2001).Auxin promotes recruitment and degradation of AUXIN/INDOLE-3-ACETIC ACID(AUX/IAA)repressors,thereby releasing AUXIN RESPONSE FACTOR(ARF)to activate transcription(Gray et al.,2001).Recent discoveries have expended this model.Cryo-electron microscopy(cryo-EM)structures of AUX1 clarified its proton(H+)-coupled import(Yang et al.,2025),and TIR1 was shown to function as an adenylate cyclase(AC),producing c AMP to activate transcription(Chen et al.,2025).Synthetic promoter studies further revealed a bi-layer ARF/cis-element code shaping cel type-specific gene expression(Martin-Arevalil o et al.,2025).
基金supported by the National High Tech Develop-ment Project of China(863 Program)(Grant No.2001AA221231).
文摘MAP kinase-interacting kinase-2(Mnk2)is one of the downstream kinasesactivated by MAP kinases.It phosphorylates the eukaryotic initiation factor 4E(elF4E),althoughthe role of elF4E phosphorylation and the role of Mnk2 in the process of proteintranslation are notwell understood.Except for elF4E,other physiological substrates of Mnk2 are still unidentified.Tolook for these unidentified substrates and to reveal the physiological function of Mnk2,weperformed a yeast two-hybrid screening with Mnk2 as the bait.The results demonstrated Mnk2 couldinteract with VHL(von Hippel-Lindau tumor suppressor),Rbx1(ring-box1)and Cul2(Cullin2)proteinsin yeast cells.Furthermore,we validated the interaction between Mnk2 and VHL proteins inmammalian cells by co-immunoprecipitation analysis.Because the three proteins VHL,Rbx1 and Cul2are all components of the CBC^(VHL)ubiquitin ligase E3 complex,it has been shown that Mnk2 caninteract with CBC^(VHL)complex,and is probably one of the newsubstrates of the CBC^(VHL)complex.Furthermore,during the interaction of Mnk2 with von Hippel-Lindau(VHL)tumor suppressor-bindingprotein 1(VBP1),it appears that Mnk2 also joins to modulate cell shape as VBP1 plays an importantrole in the process of the maturation of the cytoskeleton and in the process of morphogenesis.
