Fig. 3

CEP55 and PDLIM7 bind α‐catenin in the cytoplasm of HCC cells. A Scheme depicting the experimental setup for the identification of α-catenin binding partners (BioID approach). In presence of biotin, the ligase BirA biotinylates proteins in close proximity to α‐catenin. Biotinylated proteins are affinity purified using streptavidin pulldown and identified by mass spectrometry. Scheme adapted from “BioID Assay”, by BioRender.com (2020). Retrieved from https://app.biorender.com/biorender-templates. B Volcano plot illustrating enrichment versus statistical significance of proteins identified by mass spectrometry. The x-axis indicates the log₂-fold change (FC) and the y-axis the − log₁₀ p-value. The dashed vertical line represents the cut-off (enrichment > 1.5). Red dots indicate three factors investigated in this study: CEP55, PDLIM7, and SCRIB. C List of 34 factors with protein IDs that were identified as potential α-catenin binding partners. Candidates used for further analyses are indicated in red. D Co-IP utilizing cell extracts from HLF cells transfected with Flag-tagged human α‐catenin followed by detection of α-catenin, CEP55, or PDLIM7. SCRIB, which is a known interaction partner of the cadherin/catenin complex, was used as positive control. E PLA experiments illustrating spatial proximity of α-catenin with CEP55 and PDLIM7 in the cytoplasm of HLF and Hep3B cells. Incubation with antibodies detecting α-catenin, CEP55, or PDLIM7 alone were used as negative controls. Scale bars: 50 and 10 µm for low and high magnifications, respectively