Represses transcription by binding to the BTE site, a GC-rich DNA element, in competition with the activator SP1. It also represses transcription by interacting with the corepressor Sin3A and HDAC1. Activates RANTES expression in T-cells. Ubiquitous. The Ala/Pro-rich domain may contain discrete activation and repression subdomains and also can mediate protein-protein interactions. Phosphorylated. Belongs to the Sp1 C2H2-type zinc-finger protein family.