Fig. 1

IKZF1 and IKZF3 physically associate with RUNX1 and RUNX3 in multiple myeloma. a Scatter plot of distributed normalized spectral abundance factor (dNSAF) in FLAG-immunoprecipitates (IP) from ARP-1 cells stably expressing FLAG-tagged IKZF1 and IKZF3 upon mass spectrometry analysis. For proteins with NSAF = 0, the lowest NSAF value was arbitrarily assigned. b List of peptides for the indicated proteins. EV empty vector. c Schematic model of IKZF1/3 interactors. For a complete list of interacting proteins see Supplementary Table 1. d The cell extracts of ARP-1 (left) and OPM-1 (right) cells stably expressing FLAG-tagged IKZF1 and IKZF3 were immunoprecipitated with an anti-FLAG resin and the immunocomplexes were probed with antibodies to the indicated proteins. Specificity of RUNX1 and RUNX3 antibodies was assessed using siRNAs against RUNX1 or RUNX3 (Supplementary Figure 1a). e HEK293T cells stably expressing IKZF3 were transfected with FLAG-RUNX1 or RUNX3. FLAG-immunoprecipitates were probed with antibodies to the indicated proteins. f HEK293T cells were transfected with FLAG-tagged IKZF1 or IKZF3. The cell extracts were subjected to anti-FLAG IP and the immunocomplexes were treated with Benzonase for 30 min where indicated. IPs were probed with antibodies to the indicated proteins. g Purified GST-tagged proteins as indicated were incubated with in vitro translated FLAG-tagged RUNX1. GST pull-downs were probed with anti-FLAG antibodies. Ponceau S staining shows the expressions of GST-proteins. The red asterisk indicates GST-IKZF1, blue asterisk shows GST-IKZF3, and black asterisks show cleavage products. Unless otherwise noted, immunoblots are representative of three independent experiments