Insulin is stored in dense-core secretory granules (SGs) and is released from beta cells in two distinct phases upon glucose stimulation. Dysfunctional regulation of insulin secretion causes type 2 diabetes (T2D). Newly synthesized insulin SGs are secreted preferentially, however contribution of granule age to the different phases remains elusive. We previously developed a technique for the unequivocal labeling of age-distinct SGs (Ivanova et al., 2013). Exploitation of this method showed that young SGs display greater motility compared to older SGs due to differential interaction with the cytoskeleton (Hoboth et al., 2015). The aim of my project is to uncover potential factors involved in regulation of insulin SG aging. Further, I will study the influence of these potential candidates on SG dynamics, their susceptibility to undergo exocytosis and/or degradation in dependence of their distinct age.