title: Comprehensive proteomic analysis of developing protein bodies in maize (Zea mays) endosperm provides novel insights into its biogenesis.
abstract: Prolamins, the major cereal seed storage proteins, are sequestered and accumulated in the lumen of the endoplasmic reticulum (ER), and are directly assembled into protein bodies (PBs). The content and composition of prolamins are the key determinants for protein quality and texture-related traits of the grain. Concomitantly, the PB-inducing fusion system provides an efficient target to produce therapeutic and industrial products in plants. However, the proteome of the native PB and the detailed mechanisms underlying its formation still need to be determined. We developed a method to isolate highly purified and intact PBs from developing maize endosperm and conducted proteomic analysis of intact PBs of zein, a class of prolamine protein found in maize. We thus identified 1756 proteins, which fall into five major categories: metabolic pathways, response to stimulus, transport, development, and growth, as well as regulation. By comparing the proteomes of crude and enriched extractions of PBs, we found substantial evidence for the following conclusions: (i) ribosomes, ER membranes, and the cytoskeleton are tightly associated with zein PBs, which form the peripheral border; (ii) zein RNAs are probably transported and localized to the PB-ER subdomain; and (iii) ER chaperones are essential for zein folding, quality control, and assembly into PBs. We futher confirmed that OPAQUE1 (O1) cannot directly interact with FLOURY1 (FL1) in yeast, suggesting that the interaction between myosins XI and DUF593-containing proteins is isoform-specific. This study provides a proteomic roadmap for dissecting zein PB biogenesis and reveals an unexpected diversity and complexity of proteins in PBs.
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.|Coordinated Crop Biology Research Center, Beijing 100193, P.R. China.
authors: Guifeng
authors: G
authors: Wang
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.|Coordinated Crop Biology Research Center, Beijing 100193, P.R. China.
authors: Gang
authors: G
authors: Wang
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.
authors: Jiajia
authors: J
authors: Wang
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.
authors: Yulong
authors: Y
authors: Du
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.
authors: Dongsheng
authors: D
authors: Yao
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.
authors: Bilian
authors: B
authors: Shuai
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.
authors: Liang
authors: L
authors: Han
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and.
authors: Yuanping
authors: Y
authors: Tang
authors: Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China, and rentaosong@staff.shu.edu.cn.|Coordinated Crop Biology Research Center, Beijing 100193, P.R. China.
authors: Rentao
authors: R
authors: Song
mesh_terms: D004721:Endoplasmic Reticulum / Q000378:metabolism; D056625:Endosperm / Q000737:chemistry / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D040901:Proteomics; D012270:Ribosomes / Q000378:metabolism; D055314:Seed Storage Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism*; D015028:Zein / Q000378:metabolism
chemical_list: D055314:Seed Storage Proteins; D015028:Zein
keywords: 
  Zea mays.; Endosperm; prolamin; protein body; proteomic; storage protein