Plant ER-Plasma Membrane Contact Sites under the Lens
Direct contacts between the endoplasmic reticulum (ER) and the plasma membrane (PM) have been observed in plants for decades, but their dimensions and distributions across tissues and developmental states were unknown. McFarlane et al (on pp.478-484) quantified ER-PM contact sites in a variety of Arabidopsis tissues at different developmental stages using live cell imaging, electron microscopy and tomography. They found that ER-PM contact sites were correlated with cell expansion - with abundant contact sites observed in young cells.
The cover image shows a 3-D electron tomograph model of the extensive cortical ER (green) adjacent to the PM (magenta), and the prevalence of ER-PM contact sites (blue) in young Arabidopsis root epidermal cells. Image supplied by Heather E. McFarlane (University of Melbourne) and Bradford Ross (University of British Columbia).