| Autor: |
Riihimaa, Päivi, Nissi, Ritva, Page, Antony P., Winter, Alan D., Keskiaho, Katriina, Kivirikko, Kari I., Myllyharju, Johanna |
| Zdroj: |
Journal of Biological Chemistry; May 2002, Vol. 277 Issue: 20 p18238-18243, 6p |
| Abstrakt: |
The collagen prolyl 4-hydroxylases (EC 1.14.11.2) play a critical role in the synthesis of all collagens. The enzymes from all vertebrate species studied are α2β2tetramers, in which the β subunit is identical to protein disulfide isomerase (PDI). Two isoforms of the catalytic α subunit, PHY-1 and PHY-2, have previously been characterized from Caenorhabditis elegans. We report here on the cloning and characterization of a third C. elegansα subunit isoform, PHY-3. It is much shorter than the previously characterized vertebrate and C. elegansα subunits and shows 23–30% amino acid sequence identity to PHY-1 and PHY-2 within the catalytic C-terminal region. Recombinant PHY-3 coexpressed in insect cells with a C. elegansPDI isoform that does not associate with PHY-1 was found to be an active prolyl 4-hydroxylase. The phy-3gene consists of five exons, and its expression pattern differs distinctly from the hypodermally expressed phy-1and phy-2in that it is expressed in embryos, late larval stages, and adult nematodes, expression in the latter being restricted to the spermatheca. Nematodes homozygous for a phy-3deletion are phenotypically of the wild type and fertile, but the 4-hydroxyproline content of phy-3−/−early embryos was reduced by about 90%. PHY-3 is thus likely to be involved in the synthesis of collagens in early embryos, probably of those in the egg shell. |
| Databáze: |
Supplemental Index |
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