Cargando…

Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments

At the Golgi complex, the biosynthetic sorting center of the cell, the Arf GTPases are responsible for coordinating vesicle formation. The Arf-GEFs activate Arf GTPases and are therefore the key molecular decision-makers for trafficking from the Golgi. In Saccharomyces cerevisiae, three conserved Ar...

Descripción completa

Detalles Bibliográficos
Autores principales: Gustafson, Margaret A., Fromme, J. Christopher
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706993/
https://www.ncbi.nlm.nih.gov/pubmed/28978742
http://dx.doi.org/10.1091/mbc.E17-06-0370
_version_ 1783282330946764800
author Gustafson, Margaret A.
Fromme, J. Christopher
author_facet Gustafson, Margaret A.
Fromme, J. Christopher
author_sort Gustafson, Margaret A.
collection PubMed
description At the Golgi complex, the biosynthetic sorting center of the cell, the Arf GTPases are responsible for coordinating vesicle formation. The Arf-GEFs activate Arf GTPases and are therefore the key molecular decision-makers for trafficking from the Golgi. In Saccharomyces cerevisiae, three conserved Arf-GEFs function at the Golgi: Sec7, Gea1, and Gea2. Our group has described the regulation of Sec7, the trans-Golgi Arf-GEF, through autoinhibition, positive feedback, dimerization, and interactions with a suite of small GTPases. However, we lack a clear understanding of the regulation of the early Golgi Arf-GEFs Gea1 and Gea2. Here we demonstrate that Gea1 and Gea2 prefer neutral over anionic membrane surfaces in vitro, consistent with their localization to the early Golgi. We illustrate a requirement for a critical mass of either Gea1 or Gea2 for cell growth under stress conditions. We show that the C-terminal domains of Gea1 and Gea2 toggle roles in the cytosol and at the membrane surface, preventing membrane binding in the absence of a recruiting interaction but promoting maximum catalytic activity once recruited. We also identify the small GTPase Ypt1 as a recruiter for Gea1 and Gea2. Our findings illuminate core regulatory mechanisms unique to the early Golgi Arf-GEFs.
format Online
Article
Text
id pubmed-5706993
institution National Center for Biotechnology Information
language English
publishDate 2017
publisher The American Society for Cell Biology
record_format MEDLINE/PubMed
spelling pubmed-57069932018-02-16 Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments Gustafson, Margaret A. Fromme, J. Christopher Mol Biol Cell Articles At the Golgi complex, the biosynthetic sorting center of the cell, the Arf GTPases are responsible for coordinating vesicle formation. The Arf-GEFs activate Arf GTPases and are therefore the key molecular decision-makers for trafficking from the Golgi. In Saccharomyces cerevisiae, three conserved Arf-GEFs function at the Golgi: Sec7, Gea1, and Gea2. Our group has described the regulation of Sec7, the trans-Golgi Arf-GEF, through autoinhibition, positive feedback, dimerization, and interactions with a suite of small GTPases. However, we lack a clear understanding of the regulation of the early Golgi Arf-GEFs Gea1 and Gea2. Here we demonstrate that Gea1 and Gea2 prefer neutral over anionic membrane surfaces in vitro, consistent with their localization to the early Golgi. We illustrate a requirement for a critical mass of either Gea1 or Gea2 for cell growth under stress conditions. We show that the C-terminal domains of Gea1 and Gea2 toggle roles in the cytosol and at the membrane surface, preventing membrane binding in the absence of a recruiting interaction but promoting maximum catalytic activity once recruited. We also identify the small GTPase Ypt1 as a recruiter for Gea1 and Gea2. Our findings illuminate core regulatory mechanisms unique to the early Golgi Arf-GEFs. The American Society for Cell Biology 2017-12-01 /pmc/articles/PMC5706993/ /pubmed/28978742 http://dx.doi.org/10.1091/mbc.E17-06-0370 Text en © 2017 Gustafson and Fromme. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology.
spellingShingle Articles
Gustafson, Margaret A.
Fromme, J. Christopher
Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments
title Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments
title_full Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments
title_fullStr Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments
title_full_unstemmed Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments
title_short Regulation of Arf activation occurs via distinct mechanisms at early and late Golgi compartments
title_sort regulation of arf activation occurs via distinct mechanisms at early and late golgi compartments
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706993/
https://www.ncbi.nlm.nih.gov/pubmed/28978742
http://dx.doi.org/10.1091/mbc.E17-06-0370
work_keys_str_mv AT gustafsonmargareta regulationofarfactivationoccursviadistinctmechanismsatearlyandlategolgicompartments
AT frommejchristopher regulationofarfactivationoccursviadistinctmechanismsatearlyandlategolgicompartments