Issue Information

Cover: In Hegazy et al. (http://doi.org/10.1002/cpcb.115), the image shows the use of PLA to compare protein-protein interactions in clinical tissue specimens in situ. The interaction between the desmosomal cadherin desmoglein 1 (Dsg1^goat) and its cytoplasmic partner plakoglobin (Pg^mouse) is analyzed in a paraffin-embedded biopsy from a patient with SAM syndrome and compared to control tissue. SAM syndrome is a skin disease associated with a loss of Dsg1 expression at the cell-cell adhesive interface (Cohen-Barak et al., 2020; Samuelov et al., 2013). (A) The PLA signal is clearly decreased in the patient section compared to control tissue (red, Duolink™ In Situ Detection Reagent Red, λ_Ex: 594, λ_Em: 624). (B) A traditional immunofluorescence assay performed on control tissue is used to demonstrate successful antibody binding to both proteins analyzed by PLA (Dsg1, red; Pg, green; DAPI, blue). (C) In tissue sections such as this, using DAPI (blue) as a measure of cell number is not reliable as not every cell will have a nucleus in the cross section; therefore, the PLA signal is quantified and plotted as the area of PLA signal per field. Data points in the graph indicate the area of PLA signal in a region of the tissue. Error bars indicate the standard deviation. ImageJ/Fiji was used for image analysis and data graphed using GraphPad Prism^®. Images were acquired using an AxioVison Z1 system (Carl Zeiss) with an Apotome slide module, an AxioCam MRm digital camera, and a 40× ([0.5 NA] Plan-Neofluar) objective. Scale bar, 50 µm.