Transcriptional repressor that binds the core 5'GNNTGTNG-3' DNA consensus sequence (PubMed:10978333, PubMed:31217188). Involved in megakaryocyte differentiation. Self-associates. Interacts with other family members; IKZF1, IKZF2, IKZF3 AND IKZF4. Expressed in brain, heart, skeletal muscle, kidney, and liver. Expressed in the hematopoietic cell lines MOLT-4, NALM-6 and K-562. Highly expressed in THP-1 and M-07e cell lines, which have characteristics of myeloid and early megakaryocytic cells respectively. The N-terminal zinc fingers are involved in sequence-specific DNA binding and heterotypic associations with other family members. C-terminal zinc fingers mediate homodimerization. The disease may be caused by variants affecting the gene represented in this entry. 'Pegasus' was the winged horse in Greek mythology. Belongs to the Ikaros C2H2-type zinc-finger protein family.