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PDILT, a divergent testis-specific protein disulfide isomerase with a non-classical SXXC motif that engages in disulfide-dependent interactions in the endoplasmic reticulum

van Lith, M; Hartigan, N; Hatch, J; Benham, AM

Authors

M van Lith

N Hartigan

J Hatch



Abstract

Protein disulfide isomerase (PDI) is the archetypal enzyme involved in the formation and reshuffling of disulfide bonds in the endoplasmic reticulum (ER). PDI achieves its redox function through two highly conserved thioredoxin domains, and PDI can also operate as an ER chaperone. The substrate specificities and the exact functions of most other PDI family proteins remain important unsolved questions in biology. Here, we characterize a new and striking member of the PDI family, which we have named protein disulfide isomerase-like protein of the testis (PDILT). PDILT is the first eukaryotic SXXC protein to be characterized in the ER. Our experiments have unveiled a novel, glycosylated PDI-like protein whose tissue-specific expression and unusual motifs have implications for the evolution, catalytic function, and substrate selection of thioredoxin family proteins. We show that PDILT is an ER resident glycoprotein that liaises with partner proteins in disulfide-dependent complexes within the testis. PDILT interacts with the oxidoreductase Ero1, 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.

Citation

van Lith, M., Hartigan, N., Hatch, J., & Benham, A. (2005). PDILT, a divergent testis-specific protein disulfide isomerase with a non-classical SXXC motif that engages in disulfide-dependent interactions in the endoplasmic reticulum. Journal of Biological Chemistry, 280(2), 1376-1383. https://doi.org/10.1074/jbc.m408651200

Journal Article Type Article
Publication Date Jan 1, 2005
Deposit Date May 14, 2007
Journal Journal of Biological Chemistry
Print ISSN 0021-9258
Electronic ISSN 1083-351X
Publisher American Society for Biochemistry and Molecular Biology
Peer Reviewed Peer Reviewed
Volume 280
Issue 2
Pages 1376-1383
DOI https://doi.org/10.1074/jbc.m408651200