Alpha tubulin co-immunoprecipitates with ARX in mammalian cells. HEK293T cells transfected with Myc-ARX full length protein (FL-Wt), Myc-ARX-homeodomain (HD) or Myc-ARX-Aristaless (Arist) were lysed and proteins immunoprecipitated (IP) with mouse anti-Myc antibody. Samples were loaded on 4%-12% SDS-PAGE gels and analysed for the presence of endogenous alpha tubulin precipitated with Myc-ARX constructs by immunoblotting with rabbit anti-alpha tubulin antibody and goat anti-rabbit IgG conjugated to horseradish-peroxidase (HRP; top panel). Specific IP of Myc-ARX was achieved with no band present in samples from cells transfected with each of the Myc-ARX constructs but no IP antibody added (*). Myc-ARX full length (~62.2 kDa), Myc-ARX-HD (~19 kDa), Myc-ARX-Arist (~15 kDa) and endogenous alpha tubulin (~50 kDa) are present in crude protein lysates (bottom panel). HEK293T cells transfected with Myc-ARX NLS mutations were subjected to IP as above and alpha-tubulin was detected co-immunoprecipitating with all mutant ARX proteins (Left panel).