Size Matters: ERphagy in control of ER size.
The endoplasmic reticulum (ER) performs a myriad of diverse functions in eukaryotic cells. The spatio-temporal demands of ER processes (protein and lipid synthesis, calcium storage and signaling), mean that the ER must be able to enlarge and shrink along with changing demands. Although ER expansion is well understood, much less is known about reduction and maintenance of size. Selective ER autophagy, also known as ERphagy, has recently been observed to recycle unneeded ER membrane. Receptor driven signaling results in packaging of surplus ER membrane into an autophagosome and subsequent recycling through lysosomal fusion. In addition to ER size regulation, ERphagy has been implicated as crucial for the unfolded protein response and even viral infection. In this review we will highlight the broad relevance ER autophagy could have in basic cellular biology. We will discuss the limited advances that have been made towards understanding the signaling networks that regulate ER autophagy, and what parts of this emerging field need reinforcement and further exploration.