“At last in” the physiological roles of the tubular ER network

In eukaryotic cells, the endoplasmic reticulum (ER) forms a continuous network of tubules and sheets. ER membranes are inter-connected by a class of dynamin-like GTPases termed atlastins (ATLs). Deletion or mutation of ATLs results in long and unbranched ER tubules in cells. Mutations in ATL1 in humans have been linked to the neurodegenerative disease hereditary spastic paraplegia. The basis of ATL-mediated membrane fusion has been studied extensively, but specific functions of ATL remain unclear. In this review, we summarize ER-related cellular processes that directly or indirectly involve ATL, including membrane trafficking, lipid metabolism, autophagy, microtubule dynamics, pathogen infections, calcium signaling, and protein homeostasis. These findings provide important clues for deciphering the physiological roles of the tubular ER network.