Role of Pbr1, a putative oxidoreductase, in the ER quality control and folding of yeast Fks1 glucan synthase
Significance The budding yeast genome has long served as a foundation for understanding eukaryotic cell biology, yet a small number of essential genes have resisted functional assignment. PBR1 is one such gene: although its sequence suggested similarity to oxidoreductases, its molecular role remained unclear. Here, genome-scale functional analyses have revealed that PBR1 function converges on cell-wall biosynthesis and closely parallels that of FKS1, a multipass β-(1,3)-glucan synthase. We show that Pbr1 operates at the endoplasmic reticulum (ER) to support the folding and stability of Fks1, enabling proper cell-wall assembly. By resolving the function of a long-standing essential gene, this work reveals an ER quality-control mechanism that enables constrained membrane proteins to fold efficiently and perform essential cellular functions.