Author response image 1. Mutation of the putative phosphoinositide binding site on COMMD1 impairs the interaction with CCDC93.

HeLa cells were infected with lenti-virus expressing 3xHA-COMMD1 or 3xHA-COMMD1-EDEQE (R120E/ K129D/R133E/H134Q/K167E) mutant for 48 hours. 3xHA-COMMD1 were immunoprecipitated with HA antibodies and the precipitates were immunoblotted for CCDC93. The binding affinity for COMMD1 mutants with CCDC93 was quantified from three independent experiments. The intensity of co-immunoprecipitated CCDC93 was normalized to relevant pull-downed COMMD1. Statistical significance was analyzed using unpaired two-tailed Student’s T-test. **** P<0.0001.#.