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Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1

Protein O-mannosylation is an essential post-translational modification. It is initiated in the endoplasmic reticulum by a family of protein O-mannosyltransferases that are conserved from yeast (PMTs) to human (POMTs). The degree of functional conservation between yeast and human protein O-mannosylt...

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Autores principales: Bausewein, Daniela, Engel, Jakob, Jank, Thomas, Schoedl, Maria, Strahl, Sabine
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5016187/
https://www.ncbi.nlm.nih.gov/pubmed/27358400
http://dx.doi.org/10.1074/jbc.M116.739128
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author Bausewein, Daniela
Engel, Jakob
Jank, Thomas
Schoedl, Maria
Strahl, Sabine
author_facet Bausewein, Daniela
Engel, Jakob
Jank, Thomas
Schoedl, Maria
Strahl, Sabine
author_sort Bausewein, Daniela
collection PubMed
description Protein O-mannosylation is an essential post-translational modification. It is initiated in the endoplasmic reticulum by a family of protein O-mannosyltransferases that are conserved from yeast (PMTs) to human (POMTs). The degree of functional conservation between yeast and human protein O-mannosyltransferases is uncharacterized. In bakers' yeast, the main in vivo activities are due to heteromeric Pmt1-Pmt2 and homomeric Pmt4 complexes. Here we describe an enzymatic assay that allowed us to monitor Pmt4 activity in vitro. We demonstrate that detergent requirements and acceptor substrates of yeast Pmt4 are different from Pmt1-Pmt2, but resemble that of human POMTs. Furthermore, we mimicked two POMT1 amino acid exchanges (G76R and V428D) that result in severe congenital muscular dystrophies in humans, in yeast Pmt4 (I112R and I435D). In vivo and in vitro analyses showed that general features such as protein stability of the Pmt4 variants were not significantly affected, however, the mutants proved largely enzymatically inactive. Our results demonstrate functional and biochemical similarities between POMT1 and its orthologue from bakers' yeast Pmt4.
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spelling pubmed-50161872016-09-16 Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1 Bausewein, Daniela Engel, Jakob Jank, Thomas Schoedl, Maria Strahl, Sabine J Biol Chem Glycobiology and Extracellular Matrices Protein O-mannosylation is an essential post-translational modification. It is initiated in the endoplasmic reticulum by a family of protein O-mannosyltransferases that are conserved from yeast (PMTs) to human (POMTs). The degree of functional conservation between yeast and human protein O-mannosyltransferases is uncharacterized. In bakers' yeast, the main in vivo activities are due to heteromeric Pmt1-Pmt2 and homomeric Pmt4 complexes. Here we describe an enzymatic assay that allowed us to monitor Pmt4 activity in vitro. We demonstrate that detergent requirements and acceptor substrates of yeast Pmt4 are different from Pmt1-Pmt2, but resemble that of human POMTs. Furthermore, we mimicked two POMT1 amino acid exchanges (G76R and V428D) that result in severe congenital muscular dystrophies in humans, in yeast Pmt4 (I112R and I435D). In vivo and in vitro analyses showed that general features such as protein stability of the Pmt4 variants were not significantly affected, however, the mutants proved largely enzymatically inactive. Our results demonstrate functional and biochemical similarities between POMT1 and its orthologue from bakers' yeast Pmt4. American Society for Biochemistry and Molecular Biology 2016-08-19 2016-06-29 /pmc/articles/PMC5016187/ /pubmed/27358400 http://dx.doi.org/10.1074/jbc.M116.739128 Text en © 2016 by The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice—Final version free via Creative Commons CC-BY license (http://creativecommons.org/licenses/by/4.0) .
spellingShingle Glycobiology and Extracellular Matrices
Bausewein, Daniela
Engel, Jakob
Jank, Thomas
Schoedl, Maria
Strahl, Sabine
Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1
title Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1
title_full Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1
title_fullStr Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1
title_full_unstemmed Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1
title_short Functional Similarities between the Protein O-Mannosyltransferases Pmt4 from Bakers' Yeast and Human POMT1
title_sort functional similarities between the protein o-mannosyltransferases pmt4 from bakers' yeast and human pomt1
topic Glycobiology and Extracellular Matrices
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5016187/
https://www.ncbi.nlm.nih.gov/pubmed/27358400
http://dx.doi.org/10.1074/jbc.M116.739128
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