Figure 3: Schematic view of the β-cell arrangement within a pancreatic islet. The insulin- and C-peptide-producing β-cells interact with each other via Cx36, Pnx2, multiple cadherins, N-CAM, occludin, and several claudin isoforms. β-cells also adhere to their basal laminae (grey bands) and to those of the endothelial cells of islet capillaries (cap) by a variety of integrins. β-cells further interact with nearby glucagon-producing α-cells via Pnx1, and N-CAM. Whether a similar heterocellular interaction takes place with the somatostatin-producing δ-cells is not established. Similarly, there is no direct evidence for an interaction mediated by integral membrane proteins between β-cells and either the islet ghrelin-producing ε-cells or the pancreatic polypeptide-prodcuing PP cells.