Figure 1: Schematic representation of the membrane proteins involved in β-cell communication. Pancreatic islet cells express molecules for cell-to-cell communication, including tetraspan connexins, pannexins, occludins, and claudins, and single span cadherins, and N-CAM. Pancreatic islet cells also express molecules for cell-to-extracellular matrix communication, notably integrins. The spherical symbols on the extracellular loops of connexins and pannexins indicate the presence of highly conserved cysteine residues. The branched, dotted line on the second loop of pannexins indicates the site of glycosylation.