title: The Edges of Pancreatic Islet β Cells Constitute Adhesive and Signaling Microdomains.
abstract: Pancreatic islet β cells are organized in rosette-like structures around blood vessels and exhibit an artery-to-vein orientation, but they do not display the typical epithelial polarity. It is unclear whether these cells present a functional asymmetry related to their spatial organization. Here, we identify murine β cell edges, the sites at which adjacent cell faces meet at a sharp angle, as surface microdomains of cell-cell adhesion and signaling. The edges are marked by enrichment of F-actin and E-cadherin and are aligned between neighboring cells. The edge organization is E-cadherin contact dependent and correlates with insulin secretion capacity. Edges display elevated levels of glucose transporters and SNAP25 and extend numerous F-actin-rich filopodia. A similar β cell edge organization was observed in human islets. When stimulated, β cell edges exhibit high calcium levels. In view of the functional importance of intra-islet communication, the spatial architecture of their edges may prove fundamental for coordinating physiological insulin secretion.
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Erez
authors.initials: E
authors.lastname: Geron
authors.affiliation: Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Sigalit
authors.initials: S
authors.lastname: Boura-Halfon
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Eyal D
authors.initials: ED
authors.lastname: Schejter
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel. Electronic address: benny.shilo@weizmann.ac.il.
authors.forename: Ben-Zion
authors.initials: BZ
authors.lastname: Shilo