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Tyrosine cross-linking of extracellular matrix is catalyzed by Duox, a multidomain oxidase/peroxidase with homology to the phagocyte oxidase subunit gp91phox.

Edens WA, Sharling L, Cheng G, Shapira R, Kinkade JM, Lee T, Edens HA, Tang X, Sullards C, Flaherty DB, Benian GM, Lambeth JD - J. Cell Biol. (2001)

Bottom Line: In cuticle, collagen and other proteins are cross-linked via di- and trityrosine linkages, and these linkages were absent in RNAi animals.The expressed peroxidase domains of both Ce-Duox1 and h-Duox showed peroxidase activity and catalyzed cross-linking of free tyrosine ethyl ester.Thus, Ce-Duox catalyzes the cross-linking of tyrosine residues involved in the stabilization of cuticular extracellular matrix.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Emory University Medical School, Atlanta, GA 30322, USA.

ABSTRACT
High molecular weight homologues of gp91phox, the superoxide-generating subunit of phagocyte nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, have been identified in human (h) and Caenorhabditis elegans (Ce), and are termed Duox for "dual oxidase" because they have both a peroxidase homology domain and a gp91phox domain. A topology model predicts that the enzyme will utilize cytosolic NADPH to generate reactive oxygen, but the function of the ecto peroxidase domain was unknown. Ce-Duox1 is expressed in hypodermal cells underlying the cuticle of larval animals. To investigate function, RNA interference (RNAi) was carried out in C. elegans. RNAi animals showed complex phenotypes similar to those described previously in mutations in collagen biosynthesis that are known to affect the cuticle, an extracellular matrix. Electron micrographs showed gross abnormalities in the cuticle of RNAi animals. In cuticle, collagen and other proteins are cross-linked via di- and trityrosine linkages, and these linkages were absent in RNAi animals. The expressed peroxidase domains of both Ce-Duox1 and h-Duox showed peroxidase activity and catalyzed cross-linking of free tyrosine ethyl ester. Thus, Ce-Duox catalyzes the cross-linking of tyrosine residues involved in the stabilization of cuticular extracellular matrix.

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Related in: MedlinePlus

Tissue expression of mRNA for h-Duox. mRNA for h-Duox1, h-Duox2, and glyceraldehyde 3-phosphate dehydrogenase were detected by reverse transcriptase PCR as described in Materials and methods.
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fig3: Tissue expression of mRNA for h-Duox. mRNA for h-Duox1, h-Duox2, and glyceraldehyde 3-phosphate dehydrogenase were detected by reverse transcriptase PCR as described in Materials and methods.

Mentions: As shown in Fig. 3, h -Duox1 mRNA was distributed among a variety of adult tissues with highest expression in lung and thyroid but with significant expression also seen in placenta, testis, and prostate, and with detectable expression in pancreas and heart. h-Duox1 mRNA was also widely expressed in fetal tissues where it was abundant in lung. As reported previously (Dupuy et al., 1999), Duox2 (p138Tox) is present in thyroid. In addition, we observed significant expression in a variety of fetal tissues and in adult colon with detectable expression in kidney, liver, lung, pancreas, prostate, and testis.


Tyrosine cross-linking of extracellular matrix is catalyzed by Duox, a multidomain oxidase/peroxidase with homology to the phagocyte oxidase subunit gp91phox.

Edens WA, Sharling L, Cheng G, Shapira R, Kinkade JM, Lee T, Edens HA, Tang X, Sullards C, Flaherty DB, Benian GM, Lambeth JD - J. Cell Biol. (2001)

Tissue expression of mRNA for h-Duox. mRNA for h-Duox1, h-Duox2, and glyceraldehyde 3-phosphate dehydrogenase were detected by reverse transcriptase PCR as described in Materials and methods.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196470&req=5

fig3: Tissue expression of mRNA for h-Duox. mRNA for h-Duox1, h-Duox2, and glyceraldehyde 3-phosphate dehydrogenase were detected by reverse transcriptase PCR as described in Materials and methods.
Mentions: As shown in Fig. 3, h -Duox1 mRNA was distributed among a variety of adult tissues with highest expression in lung and thyroid but with significant expression also seen in placenta, testis, and prostate, and with detectable expression in pancreas and heart. h-Duox1 mRNA was also widely expressed in fetal tissues where it was abundant in lung. As reported previously (Dupuy et al., 1999), Duox2 (p138Tox) is present in thyroid. In addition, we observed significant expression in a variety of fetal tissues and in adult colon with detectable expression in kidney, liver, lung, pancreas, prostate, and testis.

Bottom Line: In cuticle, collagen and other proteins are cross-linked via di- and trityrosine linkages, and these linkages were absent in RNAi animals.The expressed peroxidase domains of both Ce-Duox1 and h-Duox showed peroxidase activity and catalyzed cross-linking of free tyrosine ethyl ester.Thus, Ce-Duox catalyzes the cross-linking of tyrosine residues involved in the stabilization of cuticular extracellular matrix.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, Emory University Medical School, Atlanta, GA 30322, USA.

ABSTRACT
High molecular weight homologues of gp91phox, the superoxide-generating subunit of phagocyte nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, have been identified in human (h) and Caenorhabditis elegans (Ce), and are termed Duox for "dual oxidase" because they have both a peroxidase homology domain and a gp91phox domain. A topology model predicts that the enzyme will utilize cytosolic NADPH to generate reactive oxygen, but the function of the ecto peroxidase domain was unknown. Ce-Duox1 is expressed in hypodermal cells underlying the cuticle of larval animals. To investigate function, RNA interference (RNAi) was carried out in C. elegans. RNAi animals showed complex phenotypes similar to those described previously in mutations in collagen biosynthesis that are known to affect the cuticle, an extracellular matrix. Electron micrographs showed gross abnormalities in the cuticle of RNAi animals. In cuticle, collagen and other proteins are cross-linked via di- and trityrosine linkages, and these linkages were absent in RNAi animals. The expressed peroxidase domains of both Ce-Duox1 and h-Duox showed peroxidase activity and catalyzed cross-linking of free tyrosine ethyl ester. Thus, Ce-Duox catalyzes the cross-linking of tyrosine residues involved in the stabilization of cuticular extracellular matrix.

Show MeSH
Related in: MedlinePlus