Granule Size Distribution Suggests Mechanism: The Case for Granule Growth and Elimination as a Fusion Nano-Machine

Secretory cells store a notable array of preformed molecules of various sizes in their secretory granules. When these cells are activated to degranulate, granule content is secreted through a fusion pore to the extracellular space. Analysis of secretory granule size (or content) distributions in various cells documented a periodic multimodal behavior, as would be the case under homotypic fusion of granules (Gn) with unit granules of quantal …