Sec22 and Memb11 are v-SNAREs of the anterograde endoplasmic reticulum-Golgi pathway in tobacco leaf epidermal cells

Plant Physiol. 2005 Nov;139(3):1244-54. doi: 10.1104/pp.105.067447. Epub 2005 Oct 21.

Abstract

Distinct sets of soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors (SNAREs) are distributed to specific intracellular compartments and catalyze membrane fusion events. Although the central role of these proteins in membrane fusion is established in nonplant systems, little is known about their role in the early secretory pathway of plant cells. Analysis of the Arabidopsis (Arabidopsis thaliana) genome reveals 54 genes encoding SNARE proteins, some of which are expected to be key regulators of membrane trafficking between the endoplasmic reticulum (ER) and the Golgi. To gain insights on the role of SNAREs of the early secretory pathway in plant cells, we have cloned the Arabidopsis v-SNAREs Sec22, Memb11, Bet11, and the t-SNARE Sed5, and analyzed their distribution in plant cells in vivo. By means of live cell imaging, we have determined that these SNAREs localize at the Golgi apparatus. In addition, Sec22 was also distributed at the ER. We have then focused on understanding the function of Sec22 and Memb11 in comparison to the other SNAREs. Overexpression of the v-SNAREs Sec22 and Memb11 but not of the other SNAREs induced collapse of Golgi membrane proteins into the ER, and the secretion of a soluble secretory marker was abrogated by all SNAREs. Our studies suggest that Sec22 and Memb11 are involved in anterograde protein trafficking at the ER-Golgi interface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers
  • Brefeldin A / pharmacology
  • Endoplasmic Reticulum / metabolism*
  • Genes, Reporter
  • Golgi Apparatus / metabolism*
  • Nicotiana / cytology*
  • Nicotiana / metabolism*
  • Plant Epidermis / cytology*
  • Plant Epidermis / drug effects
  • Plant Leaves / cytology*
  • Plant Leaves / metabolism
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plants, Genetically Modified
  • Protein Transport
  • Recombinant Fusion Proteins
  • SNARE Proteins / genetics
  • SNARE Proteins / metabolism*
  • Sialyltransferases / metabolism

Substances

  • Biomarkers
  • Plant Proteins
  • Recombinant Fusion Proteins
  • SNARE Proteins
  • Brefeldin A
  • Sialyltransferases