ER Sheets Get Roughed Up

The molecular machinery that shapes the endoplasmic reticulumʹs (ERʹs) membrane into ordered networks of “smooth” tubules and “rough” sheets is poorly defined. now report that sheet-inducing proteins, such as Climp-63, are enriched in the “rough” ER by their association with membrane-bound ribosomes, whereas curvature-inducing proteins localize at highly bent edges of membrane sheets.