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SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins
The human Usher syndrome (USH) is a retinal ciliopathy, characterized by profound congenital deafness, variable vestibular dysfunction and pre-pubertal onset of retinitis pigmentosa. In the effected sensory cells, USH protein networks are assumed to function in ciliary transport processes. The USH1G...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6787559/ https://www.ncbi.nlm.nih.gov/pubmed/31637240 http://dx.doi.org/10.3389/fcell.2019.00216 |
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author | Sorusch, Nasrin Yildirim, Adem Knapp, Barbara Janson, Julia Fleck, Wiebke Scharf, Caroline Wolfrum, Uwe |
author_facet | Sorusch, Nasrin Yildirim, Adem Knapp, Barbara Janson, Julia Fleck, Wiebke Scharf, Caroline Wolfrum, Uwe |
author_sort | Sorusch, Nasrin |
collection | PubMed |
description | The human Usher syndrome (USH) is a retinal ciliopathy, characterized by profound congenital deafness, variable vestibular dysfunction and pre-pubertal onset of retinitis pigmentosa. In the effected sensory cells, USH protein networks are assumed to function in ciliary transport processes. The USH1G protein SANS is a scaffold of the ciliary/periciliary USH protein network of photoreceptor cells. Moreover, SANS is associated with microtubules, the transport routes for protein delivery toward the cilium. To enlighten the role of SANS in ciliary transport processes, we aimed to identify transport related proteins associated with SANS. The intraflagellar transport (IFT) system is a conserved mechanism for bi-directional transport toward and through primary cilia. Thus, we tested the direct binding of SANS to IFT molecules, namely IFT20, IFT57, and IFT74 in 1:1 yeast-two-hybrid assay. The identified SANS-IFT interactions were validated in vitro via independent complementary interaction assays and in cells by applying membrane targeting assays. Quantitative immunofluorescence microscopy revealed the co-localization of SANS with IFT20, IFT52, and IFT57 particularly at ciliary base of wild type mouse photoreceptor cells. Analysis of photoreceptor cells of SANS knock out mice revealed the decrease of IFTs in the ciliary compartment indicating a role of SANS in the proper positioning of IFT-B molecules in primary cilia. Our study demonstrated direct binding of IFT complex B proteins IFT52 and IFT57 to the N-terminal ankyrin repeats and the central domain of SANS. Our data also indicate that pathologic mutations in the N-terminus of SANS lead to the loos of SANS binding to IFT-B molecules. Our findings provide direct evidence for a molecular link between the ciliary USH protein network and the IFT transport module in primary cilia. |
format | Online Article Text |
id | pubmed-6787559 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-67875592019-10-21 SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins Sorusch, Nasrin Yildirim, Adem Knapp, Barbara Janson, Julia Fleck, Wiebke Scharf, Caroline Wolfrum, Uwe Front Cell Dev Biol Cell and Developmental Biology The human Usher syndrome (USH) is a retinal ciliopathy, characterized by profound congenital deafness, variable vestibular dysfunction and pre-pubertal onset of retinitis pigmentosa. In the effected sensory cells, USH protein networks are assumed to function in ciliary transport processes. The USH1G protein SANS is a scaffold of the ciliary/periciliary USH protein network of photoreceptor cells. Moreover, SANS is associated with microtubules, the transport routes for protein delivery toward the cilium. To enlighten the role of SANS in ciliary transport processes, we aimed to identify transport related proteins associated with SANS. The intraflagellar transport (IFT) system is a conserved mechanism for bi-directional transport toward and through primary cilia. Thus, we tested the direct binding of SANS to IFT molecules, namely IFT20, IFT57, and IFT74 in 1:1 yeast-two-hybrid assay. The identified SANS-IFT interactions were validated in vitro via independent complementary interaction assays and in cells by applying membrane targeting assays. Quantitative immunofluorescence microscopy revealed the co-localization of SANS with IFT20, IFT52, and IFT57 particularly at ciliary base of wild type mouse photoreceptor cells. Analysis of photoreceptor cells of SANS knock out mice revealed the decrease of IFTs in the ciliary compartment indicating a role of SANS in the proper positioning of IFT-B molecules in primary cilia. Our study demonstrated direct binding of IFT complex B proteins IFT52 and IFT57 to the N-terminal ankyrin repeats and the central domain of SANS. Our data also indicate that pathologic mutations in the N-terminus of SANS lead to the loos of SANS binding to IFT-B molecules. Our findings provide direct evidence for a molecular link between the ciliary USH protein network and the IFT transport module in primary cilia. Frontiers Media S.A. 2019-10-04 /pmc/articles/PMC6787559/ /pubmed/31637240 http://dx.doi.org/10.3389/fcell.2019.00216 Text en Copyright © 2019 Sorusch, Yildirim, Knapp, Janson, Fleck, Scharf and Wolfrum. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Cell and Developmental Biology Sorusch, Nasrin Yildirim, Adem Knapp, Barbara Janson, Julia Fleck, Wiebke Scharf, Caroline Wolfrum, Uwe SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins |
title | SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins |
title_full | SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins |
title_fullStr | SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins |
title_full_unstemmed | SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins |
title_short | SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins |
title_sort | sans (ush1g) molecularly links the human usher syndrome protein network to the intraflagellar transport module by direct binding to ift-b proteins |
topic | Cell and Developmental Biology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6787559/ https://www.ncbi.nlm.nih.gov/pubmed/31637240 http://dx.doi.org/10.3389/fcell.2019.00216 |
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