Identification of a Human Homolog of the Drosophila rotated abdomen Gene (POMT1) Encoding a Putative Protein O-Mannosyl-Transferase, and Assignment to Human Chromosome 9q34.1

Jurado, L.A. Pérez; Coloma, Antonio; Cruces, Jesús

doi:10.1006/geno.1999.5819

Cited by 112 publications

(86 citation statements)

References 26 publications

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“…dPOMT1 and dPOMT2 are the Drosophila orthologs of hPOMT1 and hPOMT2, respectively. hPOMT1 localizes to 9q34 (26), and 20% of Walker-Warburg syndrome patients have mutations in hPOMT1 (12). But no mutations in hPOMT2, the human ortholog of dPOMT2, have yet been reported in Walker-Warburg syndrome patients, although dPOMT2 is needed for normal muscle development.…”

Section: Discussionmentioning

confidence: 99%

The Twisted Abdomen Phenotype of Drosophila POMT1 and POMT2 Mutants Coincides with Their Heterophilic Protein O-Mannosyltransferase Activity

Ichimiya

Manya

Ohmae

et al. 2004

Journal of Biological Chemistry

110

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Walker-Warburg syndrome, caused by mutations in protein O-mannosyltransferase-1 (POMT1), is an autosomal recessive disorder characterized by severe brain malformation, muscular dystrophy, and structural eye abnormalities. As humans have a second POMT, POMT2, we cloned each Drosophila ortholog of the human POMT genes and carried out RNA interference (RNAi) knockdown to investigate the function of these proteins in vivo. Drosophila POMT2 (dPOMT2) RNAi mutant flies showed a "twisted abdomen phenotype," in which the abdomen is twisted 30 -60°, similar to the dPOMT1 mutant. Moreover, dPOMT2 interacted genetically with dPOMT1, suggesting that the dPOMTs function in collaboration with each other in vivo. We expressed dPOMTs in Sf21 cells and measured POMT activity. dPOMT2 transferred a mannose to the dystroglycan protein only when it was coexpressed with dPOMT1. Likewise, dPOMT1 showed POMT activity only when coexpressed with dPOMT2, and neither dPOMT showed any activity by itself. Each dPOMT RNAi fly totally reduced POMT activity, despite the specific reduction in the level of each dPOMT mRNA. The expression pattern of dPOMT2 mRNA was found to be similar to that of dPOMT1 mRNA using whole mount in situ hybridization. These results demonstrate that the two dPOMTs function as a protein O-mannosyltransferase in association with each other, in vitro and in vivo, to generate and maintain normal muscle development.

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Section: Discussionmentioning

confidence: 99%

The Twisted Abdomen Phenotype of Drosophila POMT1 and POMT2 Mutants Coincides with Their Heterophilic Protein O-Mannosyltransferase Activity

Ichimiya

Manya

Ohmae

et al. 2004

Journal of Biological Chemistry

110

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“…Further chain elongation takes place in the Golgi apparatus using nucleotide activated sugars as donors. The initial mannosyltransfer reaction is catalyzed by an essential family of dolichyl phosphate-D-mannose:protein O-mannosyltransferases (PMTs) that is evolutionarily conserved from yeast to humans (5,(8)(9)(10)(11). PMTs have been identified and extensively characterized in yeast.…”

mentioning

confidence: 99%

Membrane association is a determinant for substrate recognition by PMT4 protein O -mannosyltransferases

Hutzler

Schmid

Bernard

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…3 and 4). 2 Moreover, PMT homologues have been also identified in many multicellular eukaryotes such as Drosophila melanogaster, mouse and, humans (15)(16)(17). Despite their evolutionarily conservation in fungi and throughout the animal kingdom (with the exception of Caenorhabditis elegans), PMTs are not present in green plants.…”

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confidence: 99%

Members of the Evolutionarily Conserved PMT Family of ProteinO-Mannosyltransferases Form Distinct Protein Complexes among Themselves

Girrbach

Strahl

2003

Journal of Biological Chemistry

134

152

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Protein O-mannosyltransferases (PMTs) initiate the assembly of O-mannosyl glycans, an essential protein modification. Since PMTs are evolutionarily conserved in fungi but are absent in green plants, the PMT family is a putative target for new antifungal drugs, particularly in fighting the threat of phytopathogenic fungi. The PMT family is phylogenetically classified into PMT1, PMT2, and PMT4 subfamilies, which differ in protein substrate specificity. In the model organism Saccharomyces cerevisiae as well as in many other fungi the PMT family is highly redundant, and only the simultaneous deletion of PMT1/PMT2 and PMT4 subfamily members is lethal. In this study we analyzed the molecular organization of PMT family members in S. cerevisiae. We show that members of the PMT1 subfamily (Pmt1p and Pmt5p) interact in pairs with members of the PMT2 subfamily (Pmt2p and Pmt3p) and that Pmt1p-Pmt2p and Pmt5p-Pmt3p complexes represent the predominant forms. Under certain physiological conditions, however, Pmt1p interacts also with Pmt3p, and Pmt5p with Pmt2p, suggesting a compensatory cooperation that guarantees the maintenance of O-mannosylation. Unlike the PMT1/PMT2 subfamily members, the single member of the PMT4 subfamily (Pmt4p) acts as a homomeric complex. Using mutational analyses we demonstrate that the same conserved protein domains underlie both heteromeric and homomeric interactions, and we identify an invariant arginine residue of transmembrane domain two as essential for the formation and/or stability of PMT complexes in general. Our data suggest that protein-protein interactions between the PMT family members offer a point of attack to shut down overall protein O-mannosylation in fungi.Protein O-mannosylation is an evolutionarily conserved protein modification of fundamental importance in many eukaryotes. In yeasts and fungi, the attachment of O-linked mannosyl residues to proteins of the secretory pathway is essential for cell viability (1). In particular it is indispensable for cell wall integrity and normal cellular morphogenesis (2-4). Impairment of O-mannosylation also affects the stability, localization, and/or proper function of individual proteins (5-10). Furthermore, aberrant O-mannosylation can interfere with the retrograde transport of misfolded proteins across the membrane of the endoplasmic reticulum (ER) 1 (11). O-mannosylation is not only important in yeast, but also in mammals. It was recently shown that in humans, O-mannosyl glycosylation represents a new pathomechanism for muscular dystrophy and neuronal migration disorders (12, 13).In yeast and fungi, O-mannosylation is initiated in the lumen of the ER by an essential family of protein O-mannosyltransferases (PMTs). These enzymes catalyze the transfer of mannose from dolichyl phosphate-activated mannose (Dol-PMan) to serine or threonine residues of secretory proteins (2). In Saccharomyces cerevisiae, a total of seven PMT family members (Pmt1-7p) have been identified, which share almost identical hydropathy profiles that predict the PMTs to b...

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Identification of a Human Homolog of the Drosophila rotated abdomen Gene (POMT1) Encoding a Putative Protein O-Mannosyl-Transferase, and Assignment to Human Chromosome 9q34.1

Cited by 112 publications

References 26 publications

The Twisted Abdomen Phenotype of Drosophila POMT1 and POMT2 Mutants Coincides with Their Heterophilic Protein O-Mannosyltransferase Activity

The Twisted Abdomen Phenotype of Drosophila POMT1 and POMT2 Mutants Coincides with Their Heterophilic Protein O-Mannosyltransferase Activity

Membrane association is a determinant for substrate recognition by PMT4 protein O -mannosyltransferases

Members of the Evolutionarily Conserved PMT Family of ProteinO-Mannosyltransferases Form Distinct Protein Complexes among Themselves

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