Protein Disulfide Isomerase Like Protein, Testis Expressed (PDILT)

PDILT, a divergent testis-specific protein disulfide isomerase with a non-classical SXXC motif that engages in disulfide-dependent interactions in the endoplasmic reticulum. PDILT is the first eukaryotic SXXC protein to be characterized in the ER. PDILT is an ER resident glycoprotein that liaises with partner proteins in disulfide-dependent complexes within the testis. PDILT interacts with the oxidoreductase Ero1alpha, demonstrating that the N-terminal cysteine of the CXXC sequence is not required for binding of PDI family proteins to ER oxidoreductases. The expression of PDILT, in addition to PDI in the testis, suggests that PDILT performs a specialized chaperone function in testicular cells. PDILT is an unusual PDI relative that highlights the adaptability of chaperone and redox function in enzymes of the endoplasmic reticulum.