Investigation of Par3 and RASSF7 interaction

Abstract

Cell polarity is regulated by a complex network of interactions between different polarity proteins. Par3 is a key cell polarity regulator. It is known that Par3 plays a role in epithelial apico-basal polarity regulation and cancer through its interaction with other polarity proteins. Past studies have established that Ras-association domain family 7 (RASSF7) is a centrosome-localised regulator of mitosis. Previously, preliminary evidence in support of Par3 and RASSF7 interaction was provided using affinity capture mass spectrometry and APEX2 proximity labelling. However, co-localisation and interaction between the two proteins have not been verified. In this study, co-localisation between RASSF7 and the tight junction marker, ZO-1 in MDCK-II cells was demonstrated using the expression of an EGFP-RASSF7 fusion construct and immunofluorescence, indicating that RASSF7 is a novel tight junction-localised protein. Furthermore, co-localisation of Par3 and RASSF7 was validated using immunofluorescence. However, conclusive validation of Par3 and RASSF7 interaction using co-immunoprecipitation and Western blot was not achieved due to time constraints. The results of this study provide further evidence in support of RASSF7 as a novel Par3 interaction partner and act as a foundation for more in-depth characterisation of Par3 and RASSF7 interaction in the future.