ER-associated degradation

Efstathiou et al. describe an Argonaute-dependent endoplasmic reticulum (ER)-associated RNA silencing pathway that acts together with ER-associated protein degradation to preserve ER homeostasis and function.

Sanchón et al find that misfolded proteins formed in the ER can become associated with mitochondria, both in mammalian cells and in yeast, resulting in impaired mitochondrial function. They further discover that components of ERMES-mediated ER-mitochondria contacts are needed for this mechanism, which they name ERAMS, for ER-associated mitochondrial sequestration.

Glycoprotein US9 of human cytomegalovirus downregulates the activating immune ligand MICA*008 to avoid NK cell activation. Here, Seidel et al. show that the signal peptide of US9 is cleaved unusually slowly, causing MICA*008 to be retained in the endoplasmic reticulum (ER) and degraded via the ER quality control system.

Glycosylphosphatidylinositol (GPI) anchors are found on many cell surface proteins but their biosynthesis is not fully understood. Here, the authors identify genes involved in GPI galactosylation and reveal functional connections between GPI processing, glycosphingolipid biosynthesis and ER-associated degradation.