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Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta

Heat shock protein 47 (HSP47), encoded by the SERPINH1 gene, is a molecular chaperone essential for correct folding of collagens. We report a homozygous p.(R222S) substitution in HSP47 in a child with severe osteogenesis imperfecta leading to early demise. p.R222 is a highly conserved residue locate...

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Autores principales: Syx, Delfien, Ishikawa, Yoshihiro, Gebauer, Jan, Boudko, Sergei P., Guillemyn, Brecht, Van Damme, Tim, D’hondt, Sanne, Symoens, Sofie, Nampoothiri, Sheela, Gould, Douglas B., Baumann, Ulrich, Bächinger, Hans Peter, Malfait, Fransiska
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7877763/
https://www.ncbi.nlm.nih.gov/pubmed/33524049
http://dx.doi.org/10.1371/journal.pgen.1009339
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author Syx, Delfien
Ishikawa, Yoshihiro
Gebauer, Jan
Boudko, Sergei P.
Guillemyn, Brecht
Van Damme, Tim
D’hondt, Sanne
Symoens, Sofie
Nampoothiri, Sheela
Gould, Douglas B.
Baumann, Ulrich
Bächinger, Hans Peter
Malfait, Fransiska
author_facet Syx, Delfien
Ishikawa, Yoshihiro
Gebauer, Jan
Boudko, Sergei P.
Guillemyn, Brecht
Van Damme, Tim
D’hondt, Sanne
Symoens, Sofie
Nampoothiri, Sheela
Gould, Douglas B.
Baumann, Ulrich
Bächinger, Hans Peter
Malfait, Fransiska
author_sort Syx, Delfien
collection PubMed
description Heat shock protein 47 (HSP47), encoded by the SERPINH1 gene, is a molecular chaperone essential for correct folding of collagens. We report a homozygous p.(R222S) substitution in HSP47 in a child with severe osteogenesis imperfecta leading to early demise. p.R222 is a highly conserved residue located within the collagen interacting surface of HSP47. Binding assays show a significantly reduced affinity of HSP47-R222S for type I collagen. This altered interaction leads to posttranslational overmodification of type I procollagen produced by dermal fibroblasts, with increased glycosylation and/or hydroxylation of lysine and proline residues as shown by mass spectrometry. Since we also observed a normal intracellular folding and secretion rate of type I procollagen, this overmodification cannot be explained by prolonged exposure of the procollagen molecules to the modifying hydroxyl- and glycosyltransferases, as is commonly observed in other types of OI. We found significant upregulation of several molecular chaperones and enzymes involved in procollagen modification and folding on Western blot and RT-qPCR. In addition, we showed that an imbalance in binding of HSP47-R222S to unfolded type I collagen chains in a gelatin sepharose pulldown assay results in increased binding of other chaperones and modifying enzymes. The elevated expression and binding of this molecular ensemble to type I procollagen suggests a compensatory mechanism for the aberrant binding of HSP47-R222S, eventually leading to overmodification of type I procollagen chains. Together, these results illustrate the importance of HSP47 for proper posttranslational modification and provide insights into the molecular pathomechanisms of the p.(R222S) alteration in HSP47, which leads to a severe OI phenotype.
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spelling pubmed-78777632021-02-19 Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta Syx, Delfien Ishikawa, Yoshihiro Gebauer, Jan Boudko, Sergei P. Guillemyn, Brecht Van Damme, Tim D’hondt, Sanne Symoens, Sofie Nampoothiri, Sheela Gould, Douglas B. Baumann, Ulrich Bächinger, Hans Peter Malfait, Fransiska PLoS Genet Research Article Heat shock protein 47 (HSP47), encoded by the SERPINH1 gene, is a molecular chaperone essential for correct folding of collagens. We report a homozygous p.(R222S) substitution in HSP47 in a child with severe osteogenesis imperfecta leading to early demise. p.R222 is a highly conserved residue located within the collagen interacting surface of HSP47. Binding assays show a significantly reduced affinity of HSP47-R222S for type I collagen. This altered interaction leads to posttranslational overmodification of type I procollagen produced by dermal fibroblasts, with increased glycosylation and/or hydroxylation of lysine and proline residues as shown by mass spectrometry. Since we also observed a normal intracellular folding and secretion rate of type I procollagen, this overmodification cannot be explained by prolonged exposure of the procollagen molecules to the modifying hydroxyl- and glycosyltransferases, as is commonly observed in other types of OI. We found significant upregulation of several molecular chaperones and enzymes involved in procollagen modification and folding on Western blot and RT-qPCR. In addition, we showed that an imbalance in binding of HSP47-R222S to unfolded type I collagen chains in a gelatin sepharose pulldown assay results in increased binding of other chaperones and modifying enzymes. The elevated expression and binding of this molecular ensemble to type I procollagen suggests a compensatory mechanism for the aberrant binding of HSP47-R222S, eventually leading to overmodification of type I procollagen chains. Together, these results illustrate the importance of HSP47 for proper posttranslational modification and provide insights into the molecular pathomechanisms of the p.(R222S) alteration in HSP47, which leads to a severe OI phenotype. Public Library of Science 2021-02-01 /pmc/articles/PMC7877763/ /pubmed/33524049 http://dx.doi.org/10.1371/journal.pgen.1009339 Text en © 2021 Syx et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Syx, Delfien
Ishikawa, Yoshihiro
Gebauer, Jan
Boudko, Sergei P.
Guillemyn, Brecht
Van Damme, Tim
D’hondt, Sanne
Symoens, Sofie
Nampoothiri, Sheela
Gould, Douglas B.
Baumann, Ulrich
Bächinger, Hans Peter
Malfait, Fransiska
Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta
title Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta
title_full Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta
title_fullStr Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta
title_full_unstemmed Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta
title_short Aberrant binding of mutant HSP47 affects posttranslational modification of type I collagen and leads to osteogenesis imperfecta
title_sort aberrant binding of mutant hsp47 affects posttranslational modification of type i collagen and leads to osteogenesis imperfecta
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7877763/
https://www.ncbi.nlm.nih.gov/pubmed/33524049
http://dx.doi.org/10.1371/journal.pgen.1009339
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