Present address: Bosch Institute, Anderson Stuart Building F13, University of Sydney, NSW 2006, Australia.
Cell-to-cell transport via the lumen of the endoplasmic reticulum
Article first published online: 4 APR 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 66, Issue 5, pages 806–817, June 2011
How to Cite
Barton, D. A., Cole, L., Collings, D. A., Liu, D. Y. T., Smith, P. M. C., Day, D. A. and Overall, R. L. (2011), Cell-to-cell transport via the lumen of the endoplasmic reticulum. The Plant Journal, 66: 806–817. doi: 10.1111/j.1365-313X.2011.04545.x
- Issue published online: 24 MAY 2011
- Article first published online: 4 APR 2011
- Accepted manuscript online: 19 FEB 2011 10:41AM EST
- Received 29 September 2010; revised 11 February 2011; accepted 14 February 2011; published online 4 April 2011.
- endoplasmic reticulum;
- intercellular transport;
Plasmodesmata are plasma membrane-lined channels through which cytoplasmic molecules move from cell-to-cell in plants. Most plasmodesmata contain a desmotubule, a central tube of endoplasmic reticulum (ER), that connects the ER of adjacent cells. Here we demonstrate that molecules of up to 10.4 kDa in size can move between the ER lumen of neighbouring leaf trichome or epidermal cells via the desmotubule lumen. Fluorescent molecules of up to 10 kDa, microinjected into the ER of Nicotiana trichome cells, consistently moved into the ER and nuclei of neighbouring trichome cells. This movement occurred more rapidly than movement via the cytoplasmic pathway. A fluorescent 3-kDa dextran microinjected into the ER of a basal trichome cell moved into the ER and nuclei of epidermal cells across a barrier to cytoplasmic movement. We constructed a 10.4-kDa recombinant ER-lumenal reporter protein (LRP) from a fragment of the endogenous ER-lumenal binding protein AtBIP1. Following transient expression of the LRP in the ER of Tradescantia leaf epidermal cells, it often moved into the nuclear envelopes of neighbouring cells. However, green fluorescent protein targeted to the ER lumen (ER-GFP) did not move from cell to cell. We propose that the ER lumen of plant cells is continuous with that of their neighbours, and allows movement of small ER-lumenal molecules between cells.