Figure 5.

Plants’ endoplasmic reticulum (ER)–plasma membrane (PM) junction. The ER tubules close to the PM in plants and multicellular algae form polygonal nets, and in some regions, they go across the PM and cell wall in structures known as plasmodesmata. In these structures, the ER tubule, known as a desmotubule, is kept at different distances from the PM depending on the accumulation of callose in the cell wall or the presence of proteins such as actin in the intermembrane space.