van Lith, M. and Karala, A. and Bown, D. and Gatehouse, J. and Ruddock, L. and Saunders, P and Benham, A. M. (2007) 'A developmentally regulated chaperone complex for the endoplasmic reticulum of male haploid germ cells.', Molecular biology of the cell., 18 (8). pp. 2795-2804.
Glycoprotein folding is mediated by lectin-like chaperones and protein disulfide isomerases (PDIs) in the endoplasmic reticulum (ER). Calnexin and the PDI homologue ERp57 work together to help fold nascent polypeptides with glycans located toward the N-terminus of a protein, whereas PDI and BiP may engage proteins that lack glycans or have sugars toward the C-terminus. In this study, we show that the PDI homologue PDILT is expressed exclusively in post-meiotic male germ cells, in contrast to the ubiquitous expression of many other PDI family members in the testis. PDILT is induced during puberty and represents the first example of a PDI family member under developmental control. We find that PDILT is not active as an oxido-reductase, but interacts with the model peptide -somatostatin and nonnative BPTI in vitro, indicative of chaperone activity. In vivo, PDILT forms a tissue-specific chaperone complex with the calnexin homologue calmegin. The identification of a redox-inactive chaperone partnership defines a new system of testis-specific protein folding with implications for male fertility.
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|Publisher Web site:||http://dx.doi.org/10.1091/mbc.E07-02-0147|
|Publisher statement:||© 2007 by The American Society for Cell Biology|
|Record Created:||01 Oct 2008|
|Last Modified:||30 Aug 2011 09:19|
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