(A) In the existing model of GSIS, the first phase of insulin secretion results from a RRP composed of docked insulin granules (old face); the second phase of secretion results from a RP composed of granules located farther away (resting newcomer) that are newly recruited upon stimulation, docked, and fused to the plasma membrane. (B) In the new model, both phases consist of insulin granules that are recruited upon stimulation and immediately fused to the plasma membrane (restless newcomer). A RRP responsible for the first phase is located more than 50 nm from the plasma membrane, yet is immediately releasable. The second phase of insulin secretion involves exocytosis of insulin granules from a RP associated with the cortical actin network regulated by glucose-evoked signals in a mechanism yet to be elucidated.