Interacts with EP300 and acts as a repressor of MYOD-dependent transcription and muscle differentiation. Inhibits EP300 histone acetyltransferase activity. Acts as a repressor of TGFB/SMAD transcriptional responses. May act as a repressor of the TGFB/SMAD3-dependent signaling by selectively blocking formation of TGFB-induced SMAD3-SMAD4 complex (By similarity). Heterodimer with EID2B. Interacts with the C-terminus of EP300. Interacts with HDAC1 and HDAC2. Interacts with SMAD2, SMAD4 and with the MH2 domain of SMAD3 (By similarity). Expressed in heart, brain, kidney and pancreas. Not detected in placenta. First detected at 10.5 dpc with highest expression at 11.5 dpc. Expression decreases during later stages of development at 12.5 dpc and 14.5 dpc (at protein level). The N-terminal portion of EID2 is required for nuclear localization.