Overexpression of Arabidopsis Sorting Nexin AtSNX2b Inhibits Endocytic Trafficking to the Vacuole

作     者：Nguyen Q. Phan 

作者机构：Department of Genetics Development and Cell Biology Iowa State University Ames IA 50011 USA Interdepartmental Genetics Program Iowa State University Ames IA 50011 USA Plant Sciences Institute Iowa State University Ames IA 50011 USA 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2008年第1卷第6期

页      面：961-976页

核心收录：

学科分类：081703[工学-生物化工] 07[理学] 08[工学] 09[农学] 071007[理学-遗传学] 090102[农学-作物遗传育种] 0710[理学-生物学] 0817[工学-化学工程与技术] 0901[农学-作物学] 0902[农学-园艺学] 0836[工学-生物工程] 082203[工学-发酵工程] 0822[工学-轻工技术与工程] 

基　　金：This work was supported by the National Science Foundation (grant number IOB-0515998 to D.C.B.) and the Iowa State University Plant Sciences Institute (grant to D.C.B.). We thank Drs Chris Hawes  Erik Nielsen  David Oliver  Natasha Raikhel  and Tony Sanderfoot for antibodies  constructs  and transgenic lines  Margie Carter (ISU Confocal Microscopy and Image Analysis Facility)  and Tracey Pepper (ISU Microscopy and Nanoimaging Facility) for valuable assistance and expertise in microscopy and Tony Contento for helpful comments on the manuscript. No conflict of interest declared 

主　　题：phox homology Overexpression Vacuole 

摘      要：Sorting nexins are conserved proteins that function in vesicular trafficking and contain a characteristic phox homology （PX） domain. Here, we characterize the ubiquitously expressed Arabidopsis thaliana sorting nexin AtSNX2b. Sub-cellular fractionation studies indicate that AtSNX2b is peripherally associated with membranes. The AtSNX2b PX domain binds to phosphatidylinositol 3-phosphate in vitro and this association is required for the localization of GFPAtSNX2b to punctate structures in vivo, identified as the trans-Golgi network, prevacuolar compartment and endosomes. Overexpression of GFP-tagged AtSNX2b produces enlarged GFP-labeled compartments that can also be labeled by the endocytic tracer FM4-64. Endocytic trafficking of FM4-64 to the vacuole is arrested in these GFP-AtSNX2b compartments, and similar FM4-64-accumulating compartments are seen upon overexpression of untagged AtSNX2b. This suggests that exit of membrane components from these enlarged or aggregated endosomes is inhibited. Vacuolar proteins containing an N-terminal propeptide, but not those with a C-terminal propeptide, are also present in these enlarged compartments. We hypothesize that AtSNX2b is involved in vesicular trafficking from endosomes to the vacuole.