Advanced search
Start date
Betweenand
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

Full text
Author(s):
Marcelino da Silva, Elaine Zayas ; Freitas-Filho, Edismauro Garcia ; de Souza-Junior, Devandir Antonio ; Pinto DaSilva, Luis Lamberti ; Jamur, Maria Celia ; Oliver, Constance
Total Authors: 6
Document type: Journal article
Source: PLoS One; v. 12, n. 3 MAR 8 2017.
Web of Science Citations: 2
Abstract

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 organ-elles. ShRNA mediated depletion of the AP-3 delta subunit was shown to destabilize the AP-3 complex in RBL-2H3 MCs. AP-3 knockdown significantly affected MC regulated secretion of beta-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. (AU)

FAPESP's process: 14/11396-5 - The role of adaptor protein complex 3 (AP-3) in regulated secretion in mast cells
Grantee:Constance Oliver
Support type: Regular Research Grants
FAPESP's process: 13/12861-0 - The role of mast cell specific gangliosides in modulating mediator release
Grantee:Edismauro Garcia Freitas Filho
Support type: Scholarships in Brazil - Master
FAPESP's process: 09/54013-0 - Functional correlation between mast cells and tumor angiogenesis
Grantee:Maria Célia Jamur
Support type: Multi-user Equipment Program