CYSTEINE AND GLUTATHIONE SECRETION IN RESPONSE TO PROTEIN DISULFIDE BOND FORMATION IN THE ER

Protein folding in the endoplasmic reticulum(ER) often involves the fo rmation of disulfide bonds, The oxidizing conditions required within t his organelle were shown to be maintained through the release of small thiols, mainly cysteine and glutathione, Thiol secretion was stimulat ed when proteins rich in disulfide bonds were translocated into the ER , and secretion was prevented by the inhibition of protein synthesis, Endogenously generated cysteine and glutathione counteracted thiol-med iated retention in the ER and altered the extracellular redox, The sec retion of thiols might link disulfide bond formation in the ER to intr a-and intercellular redox signaling.