Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in the gene encoding MLC1, a membrane protein mainly expressed in astrocytes in the central nervous system. Although MLC1 function is unknown, evidence is emerging that it may regulate ion f...
Autores principales: | , , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Academic Press
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4003525/ https://www.ncbi.nlm.nih.gov/pubmed/24561067 http://dx.doi.org/10.1016/j.nbd.2014.02.003 |
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author | Brignone, Maria S. Lanciotti, Angela Visentin, Sergio De Nuccio, Chiara Molinari, Paola Camerini, Serena Diociaiuti, Marco Petrini, Stefania Minnone, Gaetana Crescenzi, Marco Laudiero, Luisa Bracci Bertini, Enrico Petrucci, Tamara C. Ambrosini, Elena |
author_facet | Brignone, Maria S. Lanciotti, Angela Visentin, Sergio De Nuccio, Chiara Molinari, Paola Camerini, Serena Diociaiuti, Marco Petrini, Stefania Minnone, Gaetana Crescenzi, Marco Laudiero, Luisa Bracci Bertini, Enrico Petrucci, Tamara C. Ambrosini, Elena |
author_sort | Brignone, Maria S. |
collection | PubMed |
description | Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in the gene encoding MLC1, a membrane protein mainly expressed in astrocytes in the central nervous system. Although MLC1 function is unknown, evidence is emerging that it may regulate ion fluxes. Using biochemical and proteomic approaches to identify MLC1 interactors and elucidate MLC1 function we found that MLC1 interacts with the vacuolar ATPase (V-ATPase), the proton pump that regulates endosomal acidity. Because we previously showed that in intracellular organelles MLC1 directly binds Na, K-ATPase, which controls endosomal pH, we studied MLC1 endosomal localization and trafficking and MLC1 effects on endosomal acidity and function using human astrocytoma cells overexpressing wild-type (WT) MLC1 or MLC1 carrying pathological mutations. We found that WT MLC1 is abundantly expressed in early (EEA1(+), Rab5(+)) and recycling (Rab11(+)) endosomes and uses the latter compartment to traffic to the plasma membrane during hyposmotic stress. We also showed that WT MLC1 limits early endosomal acidification and influences protein trafficking in astrocytoma cells by stimulating protein recycling, as revealed by FITC-dextran measurement of endosomal pH and transferrin protein recycling assay, respectively. WT MLC1 also favors recycling to the plasma-membrane of the TRPV4 cation channel which cooperates with MLC1 to activate calcium influx in astrocytes during hyposmotic stress. Although MLC disease-causing mutations differentially affect MLC1 localization and trafficking, all the mutated proteins fail to influence endosomal pH and protein recycling. This study demonstrates that MLC1 modulates endosomal pH and protein trafficking suggesting that alteration of these processes contributes to MLC pathogenesis. |
format | Online Article Text |
id | pubmed-4003525 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Academic Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-40035252014-06-01 Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis Brignone, Maria S. Lanciotti, Angela Visentin, Sergio De Nuccio, Chiara Molinari, Paola Camerini, Serena Diociaiuti, Marco Petrini, Stefania Minnone, Gaetana Crescenzi, Marco Laudiero, Luisa Bracci Bertini, Enrico Petrucci, Tamara C. Ambrosini, Elena Neurobiol Dis Article Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy caused by mutations in the gene encoding MLC1, a membrane protein mainly expressed in astrocytes in the central nervous system. Although MLC1 function is unknown, evidence is emerging that it may regulate ion fluxes. Using biochemical and proteomic approaches to identify MLC1 interactors and elucidate MLC1 function we found that MLC1 interacts with the vacuolar ATPase (V-ATPase), the proton pump that regulates endosomal acidity. Because we previously showed that in intracellular organelles MLC1 directly binds Na, K-ATPase, which controls endosomal pH, we studied MLC1 endosomal localization and trafficking and MLC1 effects on endosomal acidity and function using human astrocytoma cells overexpressing wild-type (WT) MLC1 or MLC1 carrying pathological mutations. We found that WT MLC1 is abundantly expressed in early (EEA1(+), Rab5(+)) and recycling (Rab11(+)) endosomes and uses the latter compartment to traffic to the plasma membrane during hyposmotic stress. We also showed that WT MLC1 limits early endosomal acidification and influences protein trafficking in astrocytoma cells by stimulating protein recycling, as revealed by FITC-dextran measurement of endosomal pH and transferrin protein recycling assay, respectively. WT MLC1 also favors recycling to the plasma-membrane of the TRPV4 cation channel which cooperates with MLC1 to activate calcium influx in astrocytes during hyposmotic stress. Although MLC disease-causing mutations differentially affect MLC1 localization and trafficking, all the mutated proteins fail to influence endosomal pH and protein recycling. This study demonstrates that MLC1 modulates endosomal pH and protein trafficking suggesting that alteration of these processes contributes to MLC pathogenesis. Academic Press 2014-06 /pmc/articles/PMC4003525/ /pubmed/24561067 http://dx.doi.org/10.1016/j.nbd.2014.02.003 Text en © 2014 The Authors http://creativecommons.org/licenses/by-nc-nd/3.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). |
spellingShingle | Article Brignone, Maria S. Lanciotti, Angela Visentin, Sergio De Nuccio, Chiara Molinari, Paola Camerini, Serena Diociaiuti, Marco Petrini, Stefania Minnone, Gaetana Crescenzi, Marco Laudiero, Luisa Bracci Bertini, Enrico Petrucci, Tamara C. Ambrosini, Elena Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis |
title | Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis |
title_full | Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis |
title_fullStr | Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis |
title_full_unstemmed | Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis |
title_short | Megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal pH and protein trafficking in astrocytes: Relevance to MLC disease pathogenesis |
title_sort | megalencephalic leukoencephalopathy with subcortical cysts protein-1 modulates endosomal ph and protein trafficking in astrocytes: relevance to mlc disease pathogenesis |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4003525/ https://www.ncbi.nlm.nih.gov/pubmed/24561067 http://dx.doi.org/10.1016/j.nbd.2014.02.003 |
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