Proteomic analysis of MG132-treated germinating pollen reveals expression signatures associated with proteasome inhibition

PLoS One. 2014 Sep 29;9(9):e108811. doi: 10.1371/journal.pone.0108811. eCollection 2014.

Abstract

Chemical inhibition of the proteasome has been previously found to effectively impair pollen germination and tube growth in vitro. However, the mediators of these effects at the molecular level are unknown. By performing 2DE proteomic analysis, 24 differentially expressed protein spots, representing 14 unique candidate proteins, were identified in the pollen of kiwifruit (Actinidia deliciosa) germinated in the presence of the MG132 proteasome inhibitor. qPCR analysis revealed that 11 of these proteins are not up-regulated at the mRNA level, but are most likely stabilized by proteasome inhibition. These differentially expressed proteins are predicted to function in various pathways including energy and lipid metabolism, cell wall synthesis, protein synthesis/degradation and stress responses. In line with this evidence, the MG132-induced changes in the proteome were accompanied by an increase in ATP and ROS content and by an alteration in fatty acid composition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actinidia / genetics*
  • Adenosine Triphosphate / metabolism
  • Cell Wall / drug effects
  • Cell Wall / metabolism
  • Dimethyl Sulfoxide / pharmacology
  • Energy Metabolism / drug effects
  • Fatty Acids / metabolism
  • Gene Expression Profiling*
  • Germination / drug effects*
  • Leupeptins / pharmacology*
  • Lipid Metabolism / drug effects
  • Models, Biological
  • Plant Proteins / metabolism
  • Pollen / drug effects
  • Pollen / metabolism*
  • Proteasome Inhibitors / pharmacology*
  • Proteome / metabolism
  • Proteomics / methods*
  • Reactive Oxygen Species / metabolism
  • Solubility
  • Stress, Physiological / drug effects

Substances

  • Fatty Acids
  • Leupeptins
  • Plant Proteins
  • Proteasome Inhibitors
  • Proteome
  • Reactive Oxygen Species
  • Adenosine Triphosphate
  • benzyloxycarbonylleucyl-leucyl-leucine aldehyde
  • Dimethyl Sulfoxide

Grants and funding

This work was funded by the University of Insubria RFO funds to MB and by University of Urbino RFO funds to VS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.