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Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa

Rho-type GTPases are key regulators that control eukaryotic cell polarity, but their role in fungal morphogenesis is only beginning to emerge. In this study, we investigate the role of the CDC-42 – RAC – CDC-24 module in Neurospora crassa. rac and cdc-42 deletion mutants are viable, but generate hig...

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Autores principales: Araujo-Palomares, Cynthia L., Richthammer, Corinna, Seiler, Stephan, Castro-Longoria, Ernestina
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3210136/
https://www.ncbi.nlm.nih.gov/pubmed/22087253
http://dx.doi.org/10.1371/journal.pone.0027148
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author Araujo-Palomares, Cynthia L.
Richthammer, Corinna
Seiler, Stephan
Castro-Longoria, Ernestina
author_facet Araujo-Palomares, Cynthia L.
Richthammer, Corinna
Seiler, Stephan
Castro-Longoria, Ernestina
author_sort Araujo-Palomares, Cynthia L.
collection PubMed
description Rho-type GTPases are key regulators that control eukaryotic cell polarity, but their role in fungal morphogenesis is only beginning to emerge. In this study, we investigate the role of the CDC-42 – RAC – CDC-24 module in Neurospora crassa. rac and cdc-42 deletion mutants are viable, but generate highly compact colonies with severe morphological defects. Double mutants carrying conditional and loss of function alleles of rac and cdc-42 are lethal, indicating that both GTPases share at least one common essential function. The defects of the GTPase mutants are phenocopied by deletion and conditional alleles of the guanine exchange factor (GEF) cdc-24, and in vitro GDP-GTP exchange assays identify CDC-24 as specific GEF for both CDC-42 and RAC. In vivo confocal microscopy shows that this module is organized as membrane-associated cap that covers the hyphal apex. However, the specific localization patterns of the three proteins are distinct, indicating different functions of RAC and CDC-42 within the hyphal tip. CDC-42 localized as confined apical membrane-associated crescent, while RAC labeled a membrane-associated ring excluding the region labeled by CDC42. The GEF CDC-24 occupied a strategic position, localizing as broad apical membrane-associated crescent and in the apical cytosol excluding the Spitzenkörper. RAC and CDC-42 also display distinct localization patterns during branch initiation and germ tube formation, with CDC-42 accumulating at the plasma membrane before RAC. Together with the distinct cellular defects of rac and cdc-42 mutants, these localizations suggest that CDC-42 is more important for polarity establishment, while the primary function of RAC may be maintaining polarity. In summary, this study identifies CDC-24 as essential regulator for RAC and CDC-42 that have common and distinct functions during polarity establishment and maintenance of cell polarity in N. crassa.
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spelling pubmed-32101362011-11-15 Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa Araujo-Palomares, Cynthia L. Richthammer, Corinna Seiler, Stephan Castro-Longoria, Ernestina PLoS One Research Article Rho-type GTPases are key regulators that control eukaryotic cell polarity, but their role in fungal morphogenesis is only beginning to emerge. In this study, we investigate the role of the CDC-42 – RAC – CDC-24 module in Neurospora crassa. rac and cdc-42 deletion mutants are viable, but generate highly compact colonies with severe morphological defects. Double mutants carrying conditional and loss of function alleles of rac and cdc-42 are lethal, indicating that both GTPases share at least one common essential function. The defects of the GTPase mutants are phenocopied by deletion and conditional alleles of the guanine exchange factor (GEF) cdc-24, and in vitro GDP-GTP exchange assays identify CDC-24 as specific GEF for both CDC-42 and RAC. In vivo confocal microscopy shows that this module is organized as membrane-associated cap that covers the hyphal apex. However, the specific localization patterns of the three proteins are distinct, indicating different functions of RAC and CDC-42 within the hyphal tip. CDC-42 localized as confined apical membrane-associated crescent, while RAC labeled a membrane-associated ring excluding the region labeled by CDC42. The GEF CDC-24 occupied a strategic position, localizing as broad apical membrane-associated crescent and in the apical cytosol excluding the Spitzenkörper. RAC and CDC-42 also display distinct localization patterns during branch initiation and germ tube formation, with CDC-42 accumulating at the plasma membrane before RAC. Together with the distinct cellular defects of rac and cdc-42 mutants, these localizations suggest that CDC-42 is more important for polarity establishment, while the primary function of RAC may be maintaining polarity. In summary, this study identifies CDC-24 as essential regulator for RAC and CDC-42 that have common and distinct functions during polarity establishment and maintenance of cell polarity in N. crassa. Public Library of Science 2011-11-07 /pmc/articles/PMC3210136/ /pubmed/22087253 http://dx.doi.org/10.1371/journal.pone.0027148 Text en Araujo-Palomares 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, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Araujo-Palomares, Cynthia L.
Richthammer, Corinna
Seiler, Stephan
Castro-Longoria, Ernestina
Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa
title Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa
title_full Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa
title_fullStr Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa
title_full_unstemmed Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa
title_short Functional Characterization and Cellular Dynamics of the CDC-42 – RAC – CDC-24 Module in Neurospora crassa
title_sort functional characterization and cellular dynamics of the cdc-42 – rac – cdc-24 module in neurospora crassa
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3210136/
https://www.ncbi.nlm.nih.gov/pubmed/22087253
http://dx.doi.org/10.1371/journal.pone.0027148
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