High-pressure environments exert significant impact on cellular survival. In Saccharomyces cerevisiae, two endoplasmic reticulum (ER)-localized proteins, Ehg1 and Ehg2, are essential for growth under 25 MPa hydrostatic pressure. Ehg1 is a cytoplasmic peripheral membrane protein containing a critical PXFP motif for its function. Ehg2 is a two-pass transmembrane protein characterized by conserved luminal domains, essential N-glycosylation sites, and a vital cytoplasmic GVPS motif. Both proteins stabilize nutrient permeases by preventing their degradation under high-pressure conditions, thereby maintaining nutrient uptake. These findings reveal a unique adaptive strategy in which ER-localized proteins preserve membrane protein integrity during mechanical stress.
Uemura et al. (Sun,) studied this question.