Transcriptional repressor. Regulator of transcriptional factor complexes and may suppress SRE and AP-1 transcription activities mediated by growth factor signaling pathways. Highly expressed in heart, skeletal muscle, and brain. Lower expression in liver, lung, kidney, pancreas and placenta. Expressed in fetal heart, brain, placenta, lung, liver, skeletal muscle, kidney, and pancreas. The KRAB domain is required for transcriptional repression. Belongs to the krueppel C2H2-type zinc-finger protein family.