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Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium

Copines are a family of cytosolic proteins that associate with membranes in a calcium‐dependent manner and are found in many eukaryotic organisms. Dictyostelium discoideum has six copine genes (cpnA‐cpnF), and cells lacking cpnA(cpnA(−)) have defects in cytokinesis, chemotaxis, adhesion, and develop...

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Autores principales: Wight, Elise M., Ide, Amber D., Damer, Cynthia K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7262877/
https://www.ncbi.nlm.nih.gov/pubmed/32351039
http://dx.doi.org/10.1002/2211-5463.12874
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author Wight, Elise M.
Ide, Amber D.
Damer, Cynthia K.
author_facet Wight, Elise M.
Ide, Amber D.
Damer, Cynthia K.
author_sort Wight, Elise M.
collection PubMed
description Copines are a family of cytosolic proteins that associate with membranes in a calcium‐dependent manner and are found in many eukaryotic organisms. Dictyostelium discoideum has six copine genes (cpnA‐cpnF), and cells lacking cpnA(cpnA(−)) have defects in cytokinesis, chemotaxis, adhesion, and development. CpnA has also been shown to associate with the plasma membrane, contractile vacuoles (CV), and organelles of the endolysosomal pathway. Here, we use cpnA(−) cells to investigate the role of CpnA in CV function and endocytosis. When placed in water, cpnA(−) cells made abnormally large CVs that took longer to expel. Visualization of CVs with the marker protein GFP‐dajumin indicated that cpnA(−) cells had fewer CVs that sometimes refilled before complete emptying. In endocytosis assays, cpnA(−) cells took up small fluorescent beads by macropinocytosis at rates similar to parental cells. However, cpnA(−) cells reached a plateau sooner than parental cells and had less fluorescence at later time points. p80 antibody labeling of postlysosomes (PL) indicated that there were fewer and smaller PLs in cpnA(−) cells. In dextran pulse‐chase experiments, the number of PLs peaked earlier in cpnA(−) cells, and the PLs did not become as large and disappeared sooner as compared to parental cells. PLs in cpnA(−) cells were also shown to have more actin coats, suggesting CpnA may play a role in actin filament disassembly on PL membranes. Overall, these results indicate that CpnA is involved in the regulation of CV size and expulsion, and the maturation, size, and exocytosis of PLs.
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spelling pubmed-72628772020-06-01 Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium Wight, Elise M. Ide, Amber D. Damer, Cynthia K. FEBS Open Bio Research Articles Copines are a family of cytosolic proteins that associate with membranes in a calcium‐dependent manner and are found in many eukaryotic organisms. Dictyostelium discoideum has six copine genes (cpnA‐cpnF), and cells lacking cpnA(cpnA(−)) have defects in cytokinesis, chemotaxis, adhesion, and development. CpnA has also been shown to associate with the plasma membrane, contractile vacuoles (CV), and organelles of the endolysosomal pathway. Here, we use cpnA(−) cells to investigate the role of CpnA in CV function and endocytosis. When placed in water, cpnA(−) cells made abnormally large CVs that took longer to expel. Visualization of CVs with the marker protein GFP‐dajumin indicated that cpnA(−) cells had fewer CVs that sometimes refilled before complete emptying. In endocytosis assays, cpnA(−) cells took up small fluorescent beads by macropinocytosis at rates similar to parental cells. However, cpnA(−) cells reached a plateau sooner than parental cells and had less fluorescence at later time points. p80 antibody labeling of postlysosomes (PL) indicated that there were fewer and smaller PLs in cpnA(−) cells. In dextran pulse‐chase experiments, the number of PLs peaked earlier in cpnA(−) cells, and the PLs did not become as large and disappeared sooner as compared to parental cells. PLs in cpnA(−) cells were also shown to have more actin coats, suggesting CpnA may play a role in actin filament disassembly on PL membranes. Overall, these results indicate that CpnA is involved in the regulation of CV size and expulsion, and the maturation, size, and exocytosis of PLs. John Wiley and Sons Inc. 2020-05-19 /pmc/articles/PMC7262877/ /pubmed/32351039 http://dx.doi.org/10.1002/2211-5463.12874 Text en © 2020 The Authors. Published by FEBS Press and John Wiley & Sons Ltd. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Articles
Wight, Elise M.
Ide, Amber D.
Damer, Cynthia K.
Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium
title Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium
title_full Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium
title_fullStr Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium
title_full_unstemmed Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium
title_short Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium
title_sort copine a regulates the size and exocytosis of contractile vacuoles and postlysosomes in dictyostelium
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7262877/
https://www.ncbi.nlm.nih.gov/pubmed/32351039
http://dx.doi.org/10.1002/2211-5463.12874
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