Roles of molecular motors in insulin-secreting beta cells

Pancreatic β cells are essential for glucose homeostasis through the regulated secretion of insulin in response to rising glucose levels. A critical component of this process is the precise and timely positioning of insulin secretory granules (ISGs) at the secretion sites on the plasma membrane. This positioning is mediated by molecular motors that transport ISGs along cytoskeletal tracks, including microtubules (MTs) and actin filaments. Despite their importance, the roles of molecular motors in insulin-secreting β cells remain incompletely understood. In this review, we summarize current findings on the involvement of molecular motors both in ISG transport, directly regulating granule availability for secretion, and in the organization of other subcellular structures, thereby indirectly influencing secretion. These indirect roles include kinesin-1-mediated microtubule sliding that configures the β cell-specific MT network, the spatial organization of calcium channels, and mitochondrial positioning, among others. We also draw parallels between β cells and neurons, proposing that insights from neuronal motor protein studies can guide future research directions in β cell biology.