GOLGI TRANSPORT 1B Regulates Protein Export from the Endoplasmic Reticulum in Rice Endosperm Cells.
Coat protein complex II (COPII) mediates the first step of anterograde transport of newly synthesized proteins from the endoplasmic reticulum (ER) to other endomembrane compartments in eukaryotes. A group of evolutionarily conserved proteins (Sar1, Sec23, Sec24, Sec13, and Sec31) constitutes the basic COPII coat machinery; however, the details of how the COPII coat assembly is regulated remain unclear. Here, we report a protein transport mutant of rice (Oryza sativa), named glutelin precursor accumulation4 (gpa4), which accumulates 57-kD glutelin precursors and forms two types of ER-derived abnormal structures. GPA4 encodes the evolutionarily conserved membrane protein GOT1B (also known as GLUP2), homologous to the Saccharomyces cerevisiae GOT1p. The rice GOT1B protein colocalizes with Arabidopsis thaliana Sar1b at Golgi-associated ER exit sites (ERESs) when they are coexpressed in Nicotiana benthamiana Moreover, GOT1B physically interacts with rice Sec23, and both proteins are present in the same complex(es) with rice Sar1b. The distribution of rice Sar1 in the endomembrane system, its association with rice Sec23c, and the ERES organization pattern are significantly altered in the gpa4 mutant. Taken together, our results suggest that GOT1B plays an important role in mediating COPII vesicle formation at ERESs, thus facilitating anterograde transport of secretory proteins in plant cells.
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Yihua
0000-0003-1945-1277
Y
Wang
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Feng
F
Liu
National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
Yulong
0000-0002-9032-3529
Y
Ren
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Yunlong
Y
Wang
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Xi
X
Liu
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Wuhua
0000-0003-3126-2495
W
Long
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Di
D
Wang
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Jianping
0000-0002-3685-7175
J
Zhu
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Xiaopin
X
Zhu
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Ruonan
R
Jing
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Mingming
M
Wu
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Yuanyuan
Y
Hao
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Ling
L
Jiang
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Chunming
C
Wang
National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
Haiyang
0000-0002-1302-5747
H
Wang
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Yiqun
0000-0003-0066-0239
Y
Bao
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, P.R. China wanjm@njau.edu.cn.|National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
Jianmin
0000-0002-7813-4362
J
Wan
D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D056625:Endosperm / Q000235:genetics / Q000378:metabolism*; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
D044385:GTP-Binding Protein alpha Subunits; D010940:Plant Proteins