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Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release

Mast cell (MC) secretory granules are Lysosome-Related Organelles (LROs) whose biogenesis is associated with the post-Golgi secretory and endocytic pathways in which the sorting of proteins destined for a specific organelle relies on the recognition of sorting signals by adaptor proteins that direct...

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Autores principales: da Silva, Elaine Zayas Marcelino, Freitas-Filho, Edismauro Garcia, de Souza-Júnior, Devandir Antonio, daSilva, Luis Lamberti Pinto, Jamur, Maria Celia, Oliver, Constance
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5342237/
https://www.ncbi.nlm.nih.gov/pubmed/28273137
http://dx.doi.org/10.1371/journal.pone.0173462
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author da Silva, Elaine Zayas Marcelino
Freitas-Filho, Edismauro Garcia
de Souza-Júnior, Devandir Antonio
daSilva, Luis Lamberti Pinto
Jamur, Maria Celia
Oliver, Constance
author_facet da Silva, Elaine Zayas Marcelino
Freitas-Filho, Edismauro Garcia
de Souza-Júnior, Devandir Antonio
daSilva, Luis Lamberti Pinto
Jamur, Maria Celia
Oliver, Constance
author_sort da Silva, Elaine Zayas Marcelino
collection PubMed
description Mast cell (MC) secretory granules are Lysosome-Related Organelles (LROs) whose biogenesis is associated with the post-Golgi secretory and endocytic pathways in which the sorting of proteins destined for a specific organelle relies on the recognition of sorting signals by adaptor proteins that direct their incorporation into transport vesicles. The adaptor protein 3 (AP-3) complex mediates protein trafficking between the trans-Golgi network (TGN) and late endosomes, lysosomes, and LROs. AP-3 has a recognized role in LROs biogenesis and regulated secretion in several cell types, including many immune cells such as neutrophils, natural killer cells, and cytotoxic T lymphocytes. However, the relevance of AP-3 for these processes in MCs has not been previously investigated. AP-3 was found to be expressed and distributed in a punctate fashion in rat peritoneal mast cells ex vivo. The rat MC line RBL-2H3 was used as a model system to investigate the role of AP-3 in mast cell secretory granule biogenesis and mediator release. By immunofluorescence and immunoelectron microscopy, AP-3 was localized both to the TGN and early endosomes indicating that AP-3 dependent sorting of proteins to MC secretory granules originates in these organelles. ShRNA mediated depletion of the AP-3 δ subunit was shown to destabilize the AP-3 complex in RBL-2H3 MCs. AP-3 knockdown significantly affected MC regulated secretion of β-hexosaminidase without affecting total cellular enzyme levels. Morphometric evaluation of MC secretory granules by electron microscopy revealed that the area of MC secretory granules in AP-3 knockdown MCs was significantly increased, indicating that AP-3 is involved in MC secretory granule biogenesis. Furthermore, AP-3 knockdown had a selective impact on the secretion of newly formed and newly synthesized mediators. These results show for the first time that AP-3 plays a critical role in secretory granule biogenesis and mediator release in MCs.
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spelling pubmed-53422372017-03-29 Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release da Silva, Elaine Zayas Marcelino Freitas-Filho, Edismauro Garcia de Souza-Júnior, Devandir Antonio daSilva, Luis Lamberti Pinto Jamur, Maria Celia Oliver, Constance PLoS One Research Article Mast cell (MC) secretory granules are Lysosome-Related Organelles (LROs) whose biogenesis is associated with the post-Golgi secretory and endocytic pathways in which the sorting of proteins destined for a specific organelle relies on the recognition of sorting signals by adaptor proteins that direct their incorporation into transport vesicles. The adaptor protein 3 (AP-3) complex mediates protein trafficking between the trans-Golgi network (TGN) and late endosomes, lysosomes, and LROs. AP-3 has a recognized role in LROs biogenesis and regulated secretion in several cell types, including many immune cells such as neutrophils, natural killer cells, and cytotoxic T lymphocytes. However, the relevance of AP-3 for these processes in MCs has not been previously investigated. AP-3 was found to be expressed and distributed in a punctate fashion in rat peritoneal mast cells ex vivo. The rat MC line RBL-2H3 was used as a model system to investigate the role of AP-3 in mast cell secretory granule biogenesis and mediator release. By immunofluorescence and immunoelectron microscopy, AP-3 was localized both to the TGN and early endosomes indicating that AP-3 dependent sorting of proteins to MC secretory granules originates in these organelles. ShRNA mediated depletion of the AP-3 δ subunit was shown to destabilize the AP-3 complex in RBL-2H3 MCs. AP-3 knockdown significantly affected MC regulated secretion of β-hexosaminidase without affecting total cellular enzyme levels. Morphometric evaluation of MC secretory granules by electron microscopy revealed that the area of MC secretory granules in AP-3 knockdown MCs was significantly increased, indicating that AP-3 is involved in MC secretory granule biogenesis. Furthermore, AP-3 knockdown had a selective impact on the secretion of newly formed and newly synthesized mediators. These results show for the first time that AP-3 plays a critical role in secretory granule biogenesis and mediator release in MCs. Public Library of Science 2017-03-08 /pmc/articles/PMC5342237/ /pubmed/28273137 http://dx.doi.org/10.1371/journal.pone.0173462 Text en © 2017 da Silva 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 (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
da Silva, Elaine Zayas Marcelino
Freitas-Filho, Edismauro Garcia
de Souza-Júnior, Devandir Antonio
daSilva, Luis Lamberti Pinto
Jamur, Maria Celia
Oliver, Constance
Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release
title Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release
title_full Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release
title_fullStr Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release
title_full_unstemmed Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release
title_short Adaptor protein-3: A key player in RBL-2H3 mast cell mediator release
title_sort adaptor protein-3: a key player in rbl-2h3 mast cell mediator release
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5342237/
https://www.ncbi.nlm.nih.gov/pubmed/28273137
http://dx.doi.org/10.1371/journal.pone.0173462
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