Lipid transport protein ORP2A promotes glucose signaling by facilitating RGS1 degradation

文献类型: 外文期刊

第一作者: Yu, Qian

作者: Yu, Qian;Sun, Jialu;Sun, Mengyao;Ge, Lei;Zou, Wenjiao;Liu, Kui;Chao, Yanru;Zhang, Qianqian;Wang, Xiaodong;Wang, Xiaofei;Ge, Lei;Zou, Wenjiao;Liu, Kui;Zhang, Qianqian

作者机构:

期刊名称:PLANT PHYSIOLOGY ( 影响因子:7.4; 五年影响因子:8.7 )

ISSN: 0032-0889

年卷期: 2023 年

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收录情况: SCI

摘要: Heterotrimeric GTP-binding proteins (G proteins) are a group of regulators essential for signal transmission into cells. Regulator of G protein signaling 1 (AtRGS1) possesses intrinsic GTPase-accelerating protein (GAP) activity and could suppress G protein and glucose signal transduction in Arabidopsis (Arabidopsis thaliana). However, how AtRGS1 activity is regulated is poorly understood. Here, we identified a knockout mutant of oxysterol binding protein-related protein 2A, orp2a-1, which exhibits similar phenotypes to the arabidopsis g-protein beta 1-2 (agb1-2) mutant. Transgenic lines overexpressing ORP2A displayed short hypocotyls, a hypersensitive response to sugar, and lower intracellular AtRGS1 levels than the control. Consistently, ORP2A interacted with AtRGS1 in vitro and in vivo. Tissue-specific expression of 2 ORP2A alternative splicing isoforms implied functions in controlling organ size and shape. Bioinformatic data and phenotypes of orp2a-1, agb1-2, and the orp2a-1 agb1-2 double mutant revealed the genetic interactions between ORP2A and G beta in the regulation of G protein signaling and sugar response. Both alternative protein isoforms of ORP2A localized in the endoplasmic reticulum (ER), plasma membrane (PM), and ER-PM contact sites and interacted with vesicle-associated membrane protein-associated protein 27-1 (VAP27-1) in vivo and in vitro through their two phenylalanines in an acidic track-like motif. ORP2A also displayed differential phosphatidyl phosphoinositide binding activity mediated by the pleckstrin homology domain in vitro. Taken together, the Arabidopsis membrane protein ORP2A interacts with AtRGS1 and VAP27-1 to positively regulate G protein and sugar signaling by facilitating AtRGS1 degradation. Lipid transport protein ORP2A promotes sugar response and G protein signaling in Arabidopsis through facilitating the degradation of a negative regulator of G protein signaling.

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