Transient fusion ensures granule replenishment to enable repeated release after IgE-mediated mast cell degranulation.
To ensure normal immune function, mast cells employ different pathways to release mediators. Here, we report a thus far unknown capacity of mast cells to recycle and reuse secretory granules after an antigen-evoked degranulation process under physiological conditions; this phenomenon involves the existence of a recycling secretory granule pool that is available for release in a short time scale. Rapid endocytic modes contributed to the recycling of ∼60% of the total secretory granule population, which involved kiss-and-run and cavicapture mechanisms, causing retention of the intragranular matrix. We found the presence of normal-size granules and giant actomyosin- and dynamin-dependent granules, which were characterized by large quantal content. These large structures allowed the recovered mast cells to release a large amount of 5-HT, compensating for the decrease in the number of exocytosed secretory granules. This work uncovers a new physiological role of the exo-endocytosis cycle in the immunological plasticity of mast cells and reveals a new property of their biological secretion.
Departamento Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de 41009 Sevilla, Spain.
Santiago
S
Balseiro-Gomez
Departamento Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de 41009 Sevilla, Spain.
Juan A
JA
Flores
Departamento Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de 41009 Sevilla, Spain.
Jorge
J
Acosta
Departamento Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de 41009 Sevilla, Spain.
M Pilar
MP
Ramirez-Ponce
Departamento Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de 41009 Sevilla, Spain eales@us.es.
Eva
0000-0002-5536-4616
E
Ales
D000199:Actins / Q000378:metabolism; D000818:Animals; D000941:Antigens / Q000378:metabolism; D000001:Calcimycin / Q000494:pharmacology; D015550:Cell Degranulation / Q000187:drug effects; D034281:Dynamins / Q000378:metabolism; D055664:Electrochemical Techniques; D004705:Endocytosis / Q000187:drug effects; D005089:Exocytosis / Q000187:drug effects; D007073:Immunoglobulin E / Q000378:metabolism*; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology*; D008561:Membrane Fusion / Q000187:drug effects; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D024462:Myosin Type II / Q000378:metabolism; D022142:Secretory Vesicles / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism
D000199:Actins; D000941:Antigens; D012701:Serotonin; D007073:Immunoglobulin E; D000001:Calcimycin; D024462:Myosin Type II; D034281:Dynamins
Cavicapture; Endocytosis; Exocytosis; Kiss-and-run; Mast cell; Proteoglycan