Regulated exocytosis: new organelles for non-secretory purposes.

Regulated exocytosis is a process in which the membranes of cytoplasmic organelles fuse with the plasma membrane in response to stimulation. In many cases (secretory exocytoses), the process functions to secrete specific products that are segregated in the organelle lumen (for example, neurotransmitters, hormones and enzymes) to the extracellular space. In other cases ('non-secretory exocytoses'), it functions to transfer the organelle membrane and its components to the cell surface. Here, the general properties of non-secretory exocytoses are discussed.