Figure 2.

Cortactin colocalizes and interacts with Dsg3. (A) Under conditions of desmosome re-assembly (Ca²⁺-repletion) co-incubation with PP2 significantly reduced PV3-IgG- and AK23-induced monolayer fragmentation (n > 7; ^#p < 0.05; *p < 0.05 vs. c-IgG). (B) Immunostaining revealed that under control conditions Dsg3 and cortactin as well as phosophorylated cortactin were in part localized at cell borders, which was reduced by Ca²⁺-depletion. Following Ca²⁺-repletion for 8 h, all proteins relocated along the cell-membrane (scale bar 20 μm; n = 4). (C) Under basal conditions, Dsg3 and cortactin partly co-localized at cell borders (scale bar 20 μm; insets represent 3.2x magnifications of indicated areas; n = 3) (D) Proximity ligation assay revealed co-localization of Dsg3 and cortactin close to the cell periphery. Cells were illuminated with F-actin to localize cell-structures. Incubation with cortactin or Dsg3 only served as negative control (n = 3). (E) Immunoprecipitation (IP) of Dsg3 documented a complex of cortactin within the Triton-soluble but not the -insoluble fraction (n = 3).