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标题：Loss of GET pathway orthologs in Arabidopsis thaliana causes root hair growth defects and affects SNARE abundance
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作者：Shuping Xing ; Dietmar Gerald Mehlhorn ; Niklas Wallmeroth 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：8
页码：E1544-E1553
DOI：10.1073/pnas.1619525114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Soluble N -ethylmaleimide–sensitive factor attachment protein receptor (SNARE) proteins are key players in cellular trafficking and coordinate vital cellular processes, such as cytokinesis, pathogen defense, and ion transport regulation. With few exceptions, SNAREs are tail-anchored (TA) proteins, bearing a C-terminal hydrophobic domain that is essential for their membrane integration. Recently, the Guided Entry of Tail-anchored proteins (GET) pathway was described in mammalian and yeast cells that serve as a blueprint of TA protein insertion [Schuldiner M, et al. (2008) Cell 134(4):634–645; Stefanovic S, Hegde RS (2007) Cell 128(6):1147–1159]. This pathway consists of six proteins, with the cytosolic ATPase GET3 chaperoning the newly synthesized TA protein posttranslationally from the ribosome to the endoplasmic reticulum (ER) membrane. Structural and biochemical insights confirmed the potential of pathway components to facilitate membrane insertion, but the physiological significance in multicellular organisms remains to be resolved. Our phylogenetic analysis of 37 GET3 orthologs from 18 different species revealed the presence of two different GET3 clades. We identified and analyzed GET pathway components in Arabidopsis thaliana and found reduced root hair elongation in Atget lines, possibly as a result of reduced SNARE biogenesis. Overexpression of At GET3a in a receptor knockout (KO) results in severe growth defects, suggesting presence of alternative insertion pathways while highlighting an intricate involvement for the GET pathway in cellular homeostasis of plants.
关键词：GET pathway ; TA proteins ; SNAREs ; ER membrane ; root hairs