How the ER stays in shape.

ABSTRACT

Understanding the molecular mechanisms that control the architecture of organelles is an area of intense study. In this issue of Cell, Voeltz et al. (2006) report that two membrane proteins, Rtn4a/NogoA and DP1/Yop1p, are responsible for the generation of tubular morphology in the endoplasmic reticulum (ER). The unusual membrane topology of these proteins may directly contribute to ER curvature.