Characterization of a novel Caenorhabditis elegans prolyl 4-hydroxylase with a unique substrate specificity and restricted expression in the pharynx and excretory duct

Keskiaho, K., Kukkola, L., Page, A. P., Winter, A. D., Vuoristo, J., Sormunen, R., Nissi, R., Riihimaa, P. and Myllyharju, J. (2008) Characterization of a novel Caenorhabditis elegans prolyl 4-hydroxylase with a unique substrate specificity and restricted expression in the pharynx and excretory duct. Journal of Biological Chemistry, 283(16), pp. 10679-10689. (doi: 10.1074/jbc.M800972200)

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Publisher's URL: http://dx.doi.org/10.1074/jbc.M800972200

Abstract

Collagen prolyl 4-hydroxylases (C-P4Hs) have a critical role in collagen synthesis, since 4-hydroxyproline residues are necessary for folding of the triple-helical molecules. Vertebrate C-P4Hs are α<sub>2</sub>β<sub>2</sub> tetramers in which the β subunit is identical to protein-disulfide isomerase (PDI). Three isoforms of the catalytic α subunit, PHY-1, PHY-2, and PHY-3, have been characterized from Caenorhabditis elegans, PHY-1 and PHY-2 being responsible for the hydroxylation of cuticle collagens, whereas PHY-3 is predicted to be involved in collagen synthesis in early embryos. We have characterized transcripts of two additional C. elegans α subunit-like genes, Y43F8B.4 and C14E2.4. Three transcripts were generated from Y43F8B.4, and a polypeptide encoded by one of them, named PHY-4.1, assembled into active (PHY-4.1)<sub>2</sub>/(PDI-2)<sub>2</sub> tetramers and PHY-4.1/PDI-2 dimers when coexpressed with C. elegans PDI-2 in insect cells. The C14E2.4 transcript was found to have a frameshift leading to the absence of codons for two residues critical for P4H catalytic activity. Thus, C. elegans has altogether four functional C-P4H α subunits, PHY-1, PHY-2, PHY-3, and PHY-4.1. The tetramers and dimers containing recombinant PHY-4.1 had a distinct substrate specificity from the other C-P4Hs in that they hydroxylated poly(L-proline) and certain other proline-rich peptides, including ones that are expressed in the pharynx, in addition to collagen-like peptides. These data and the observed restricted expression of the phy-4.1 transcript and PHY-4.1 polypeptide in the pharyngeal gland cells and the excretory duct suggest that in addition to collagens, PHY-4.1 may hydroxylate additional proline-rich proteins in vivo.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Page, Professor Tony and Winter, Dr Alan
Authors: Keskiaho, K., Kukkola, L., Page, A. P., Winter, A. D., Vuoristo, J., Sormunen, R., Nissi, R., Riihimaa, P., and Myllyharju, J.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
College/School:College of Medical Veterinary and Life Sciences
College of Medical Veterinary and Life Sciences > School of Infection & Immunity
Journal Name:Journal of Biological Chemistry
Journal Abbr.:J Biol Chem.
Publisher:American Society for Biochemistry and Molecular Biology, Inc.
ISSN:0021-9258
ISSN (Online):1083-351X
Published Online:13 February 2008
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
229991The Molecular Enzymology of Collagen Assembly and Post-Translational Modification: a Nematode Model SystemAntony PageMedical Research Council (MRC)G117/290Infection Immunity and Inflammation Life Sciences
229993The Molecular Enzymology of Collagen Assembly and Post-Translational Modification: a Nematode Model SystemAntony PageMedical Research Council (MRC)G117/476III - PARASITOLOGY