Newly synthesized secretory proteins are translocated into the ER, where disulfide bonds are formed between appropriate pairs of cysteine residues, enabling acquisition of their native conformations. Ero1α and PDI are central enzymes that catalyze this series of oxidation-reduction (redox) reactions. Credit: Kenji Inaba / Kyushu University Zinc is an essential trace element that controls myriad biological processes. The delicate balance of its concentration in the body is critical; both deficiency and excess are linked to severe pathological states such as impaired immunity, delayed wound healing, and sensory dysfunctions. However, it remains unclear how zinc dysregulation leads to these cellular defects at the molecular level. In a study published in Nature Communications , researchers have revealed that zinc levels in the endoplasmic reticulum (ER) control reduction-oxidation (redox) enzymes necessary for proper protein folding.…