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Title: Protein Bodies in Leaves Exchange Contents through the Endoplasmic Reticulum

Protein bodies (PBs) are organelles found in seeds whose main function is the storage of proteins that are used during germination for sustaining growth. PBs can also be induced to form in leaves when foreign proteins are produced at high levels in the endoplasmic reticulum (ER) and when fused to one of three tags: Zera®, elastin-like polypeptides (ELP), or hydrophobin-I (HFBI). Here in this study, we investigate the differences between ELP, HFBI and Zera PB formation, packing, and communication. Our results confirm the ER origin of all three fusion-tag-induced PBs. We show that secretory pathway proteins can be sequestered into all types of PBs but with different patterns, and that different fusion tags can target a specific protein to different PBs. Zera PBs are mobile and dependent on actomyosin motility similar to ELP and HFBI PBs. We show in vivo trafficking of proteins between PBs using GFP photoconversion. We also show that protein trafficking between ELP or HFBI PBs is faster and proteins travel further when compared to Zera PBs. Our results indicate that fusion-tag-induced PBs do not represent terminally stored cytosolic organelles, but that they form in, and remain part of the ER, and dynamically communicate with each othermore » via the ER. We hypothesize that the previously documented PB mobility along the actin cytoskeleton is associated with ER movement rather than independent streaming of detached organelles.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [1]
  1. Argiculture and Agri-Food Canada, London, ON (Canada); Univ. of Western Ontario, London, ON (Canada). Dept. of Biology
  2. Cornell Univ., Ithaca, NY (United States). Dept. of Molecular Biology and Genetics
  3. VTT Technical Research Centre of Finland, Espoo (Finland)
  4. Univ. of Western Ontario, London, ON (Canada). Dept. of Biology
Publication Date:
Grant/Contract Number:
FG02-09ER16070; SC0002628
Accepted Manuscript
Journal Name:
Frontiers in Plant Science
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 1664-462X
Frontiers Research Foundation
Research Org:
Cornell Univ., Ithaca, NY (United States); Argiculture and Agri-Food Canada, London, ON (Canada)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; protein body; protein body formation; protein trafficking; zera; elastin-like polypeptides (ELP); hydrophobin (HFBI); Nicotiana benthamiana; confocal microscopy
OSTI Identifier: