Cell-cell contacts are important regulatory elements in tissue
development, organ morphogenesis and malignant tumor invasion.
In recent
in vivo studies we have identified the members of
the cadherin/catenin family of cell adhesion proteins that are
differentially expressed in the pancreas and have determined
their cell biological dynamics during dissociation and repair
of adherens junctions. To further characterize these events,
epithelial cell culture systems were used and a number of type
II protein tyrosine phosphatases (PTPs) were found to colocalize
and interact with the cadherin/catenin complex. These observations
suggest that tyrosine dephosphorylation in general and PTPs
in particular are involved in cell contact formation. Our most
recent experiments indicate 1) that inhibition of PTPs alone
dissociates pancreatic adherens junctions, 2) that cytosolic
and transmembrane PTPs are differentially expressed in acinar
cells, and 3) that a subset of them can associate with proteins
of the cadherin/catenin complex at pancreatic cell-cell adhesions.
