Calcium plays a vital role in many processes that govern beta cell function, including the production, maturation, and regulated secretion of insulin. The fidelity of these processes depends on the maintenance of calcium subcompartments and their respective transmembrane gradients, which are organized at both the cellular and organelle level. Then endoplasmic reticulum, Golgi apparatus, and secretory granules comprise a functional module referred to as the beta cell secretory pathway, through which insulin mRNA is translated and preproinsulin protein is processed to mature insulin and packaged for exocytosis. In aggregate, these organelles also represent the largest intracellular depots of calcium. Calcium dyshomeostasis arising within the integrated secretory unit of the β cell is a characteristic of Type 1 diabetes and contributes to altered insulin production and processing and impaired β cell function and survival. The goal of this work is to define changes in the expression patterns of key molecular regulators of secretory pathway calcium and proinsulin processing.
