The endoplasmic reticulum (ER) is a major subcellular feature of most eukaryotic cells, and in specialized secretory cells, like those of the pancreas, it densely packs most of the cell. It is the de facto entry point into the secretory pathway and one of its key functions is to provide an extensive intracellular membrane network that supports protein synthesis (Figure 1). This biosynthetic activity is highlighted by the large number of ribosomes that are bound tightly to much of its surface, and it is these ribosomes that synthesize the secretory and membrane protein cargoes that are ultimately destined for export from the ER to the cell surface via the Golgi complex1,2.

This content is only available as a PDF.