JXB Advance Access originally published online on July 24, 2008
Journal of Experimental Botany 2008 59(12):3395-3406; doi:10.1093/jxb/ern198
© 2008 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
RESEARCH PAPER |
Proteome and phosphoproteome analysis of starch granule-associated proteins from normal maize and mutants affected in starch biosynthesis
1Institut National de la Recherche Agronomique, Unité de Recherche Biopolymères, Interactions, Assemblages, BP 71627, F-44316 Nantes Cedex 03, France
2Department of Biochemistry, Biophysics, and Molecular Biology, 1210 Molecular Biology Building, Iowa State University, Ames, IA 50011 USA
* To whom correspondence should be addressed. E-mail: planchot{at}nantes.inra.fr
In addition to the exclusively granule-bound starch synthase GBSSI, starch granules also bind significant proportions of other starch biosynthetic enzymes, particularly starch synthases (SS) SSI and SSIIa, and starch branching enzyme (BE) BEIIb. Whether this association is a functional aspect of starch biosynthesis, or results from non-specific entrapment during amylopectin crystallization, is not known. This study utilized genetic, immunological, and proteomic approaches to investigate comprehensively the proteome and phosphoproteome of Zea mays endosperm starch granules. SSIII, BEI, BEIIa, and starch phosphorylase were identified as internal granule-associated proteins in maize endosperm, along with the previously identified proteins GBSS, SSI, SSIIa, and BEIIb. Genetic analyses revealed three instances in which granule association of one protein is affected by the absence of another biosynthetic enzyme. First, eliminating SSIIa caused reduced granule association of SSI and BEIIb, without affecting GBSS abundance. Second, eliminating SSIII caused the appearance of two distinct electrophoretic mobility forms of BEIIb, whereas only a single migration form of BEIIb was observed in wild type or any other mutant granules examined. Third, eliminating BEIIb caused significant increases in the abundance of BEI, BEIIa, SSIII, and starch phosphorylase in the granule, without affecting SSI or SSIIa. Analysis of the granule phosphoproteome with a phosphorylation-specific dye indicated that GBSS, BEIIb, and starch phosphorylase are all phosphorylated as they occur in the granule. These results suggest the possibility that starch metabolic enzymes located in granules are regulated by post-translational modification and/or protein–protein interactions.
Key words: Protein phosphorylation, proteomics, starch biosynthesis, starch granules, Zea mays
Received 25 April 2008; Revised 9 June 2008 Accepted 24 June 2008
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  T. A. Hennen-Bierwagen, Q. Lin, F. Grimaud, V. Planchot, P. L. Keeling, M. G. James, and A. M. Myers Proteins from Multiple Metabolic Pathways Associate with Starch Biosynthetic Enzymes in High Molecular Weight Complexes: A Model for Regulation of Carbon Allocation in Maize Amyloplasts Plant Physiology, March 1, 2009; 149(3): 1541 - 1559. [Abstract] [Full Text] [PDF]
|
|