AtRGS1胞吞动态调控G蛋白参与拟南芥生长发育和抗性反应

Endocytosis of AtRGS1 Involved in the Regulation of G-proteinmediated Arabidopsis Development and Stress Responses

异源三聚体G蛋白由Gα、Gβ和Gγ 3个亚基组成,是普遍存在于真核细胞中的跨膜信号转导因子。植物细胞通过定位于细胞质膜的G蛋白信号调节子RGS蛋白(regulator of G protein signaling),调控异源三聚体G蛋白的活性,进而参与生长发育、激素和糖信号转导以及抗病反应等多个重要生物学过程。膜蛋白可通过胞吞循环调控其在细胞质膜上的数量,以响应外界环境因子和自身发育信号。近年来,研究表明多种外界信号诱导拟南芥AtRGS1蛋白的胞吞,进而促进其与Gα亚基的解离,游离的Gα-GTP、Gβγ亚基和定位于内含体的AtRGS1蛋白均可能调控下游信号转导,进而影响相应生物学过程。本文综述了AtRGS1通过胞吞作用调控G蛋白参与的生长发育和抗性反应的分子细胞学机制研究进展,以期为深入理解G蛋白信号调节子影响植物发育进程和抗性反应的作用机制提供理论参考,为植物膜蛋白胞吞调控信号转导提供新的视角。

Heterotrimeric G protein complex,classically consisting of Gα,Gβ,and Gγsubunits,mediates an essential signaling pathway across the PM(plasma membrane)in most eukaryotes.In plants,heterotrimeric G proteins regulate multiple biological processes such as plant growth and development,hormones and sugar signal transduction,and defense processes via RGS(regulator of G-protein signaling protein)protein in PM.The endocytosis of PM-localized proteins is involved in the control of their quantity on the PM in response to environmental stimuli and development signals.In Arabidopsis,several studies recently revealed that various external signals induced the endocytosis of AtRGS1,thus promoted the dissociation of AtRGS1 from Gα.Free Gα-GTP,Gβγsubgroup,and internalized AtRGS1 protein could regulate downstream signal transduction,thus affect the corresponding biological processes.In this review,we give an overview of the molecular cytological mechanism of AtRGS1 endocytosis in G-protein-mediated plant development and stress responses in Arabidopsis,aiming to provide a theoretical reference for deep understanding how RGS affects the plants development process and stress responses,as well as shed a new insight on the regulation of signal transduction by endocytosis of PM proteins.