Keeping goblet cells unstressed: new insights into a general principle

Two new studies reveal how the unfolded protein response is regulated in mucin-secreting gut epithelial cells.

Dynamic "Cap"-abilities of P-bodies and the XRN1-EDC4 axis

RNA turnover regulates the quality and quantity of cellular gene expression through a coordinated cavalcade of enzymes, factors, and phase transitions. In this issue, Brothers et al reveal the importance of balanced communication between the Xrn1 exonuclease and the EDC4 decapping factor to coordinate P-body dynamics and maintain cellular fitness.

MitoStores: a place for precursors to ride out the storm

The fate of unimported mitochondrial precursors has been increasingly studied in recent years, mostly focusing on protein degradation. In this issue of the EMBO journal, Krämer et al discovered MitoStores, a new protective mechanism that temporarily stores mitochondrial proteins in cytosolic deposits.

Calnexin reveals a sugar-free taste within the lipid bilayer

Maturation of membrane proteins is complicated by the need to fold in three distinct environments. While much is known about folding in the two aqueous milieus constituted by cytoplasm and ER lumen, our knowledge of the folding, arrangement, and quality control of transmembrane regions within the lipid bilayer, and its facilitation by molecular chaperones, is limited. New work by Bloemeke et al now reveals an expanded role of the ER chaperone calnexin acting within the lipid bilayer in a carbohydrate-independent manner.

Hold the fold: how delayed folding aids protein secretion

In bacteria, N-terminal signal peptides mark proteins for transport across the plasma membrane. A recent study by Smets et al (2022) followed the folding of a pair of structural twins to shed light on how evolution has optimised the secretory process.