ELL contains 2 separable protein-protein interaction domains.

The amino-terminus of ELL binds to both EAF2 and EAF1, but the carboxy-terminus of ELL binds only to EAF1. 293 cells were transfected with FLAG-tagged constructs containing multiple regions of ELL, immunoprecipitated with the FLAG antibody, and probed with either the 1E6 EAF1 antibody or the 1F11 EAF2 antibody. The top panel shows the expression of the FLAG-tagged ELL constructs detected with the FLAG antibody. Endogenous EAF1 coprecipitated with both the amino-terminus (residues 1-210) and the carboxy-terminus (residues 401-621) of ELL (middle panel). Endogenous EAF2 coprecipitated with amino acids 1-210 of ELL but did not coprecipitate with ELL amino acids 46-621, the region of ELL contributed to the MLL-ELL fusion protein (bottom panel).