PHD finger found in the Sp100/Sp140 family of nuclear body components
The Sp100/Sp140 family includes nuclear body proteins SP100, SP140, and similar proteins. Sp110, also termed interferon-induced protein 41/75, or speckled 110 kDa, or transcriptional coactivator Sp110, is a leukocyte-specific component of the nuclear body. It may function as a nuclear hormone receptor transcriptional coactivator that may play a role in inducing differentiation of myeloid cells. It is also involved in resisting intracellular pathogens and functions as an important drug target for preventing intracellular pathogen diseases, such as tuberculosis, hepatic veno-occlusive disease, and intracellular cancers. Sp110 gene polymorphisms may be associated with susceptibility to tuberculosis in Chinese population. Sp110 contains a Sp100-like domain, a SAND domain, a plant homeodomain (PHD) finger, and a bromodomain (BRD). SP140, also termed lymphoid-restricted homolog of Sp100 (LYSp100), or nuclear autoantigen Sp-140, or speckled 140 kDa, is an interferon inducible nuclear leukocyte-specific protein involved in primary biliary cirrhosis and a risk factor in chronic lymphocytic leukemia. It is also implicated in innate immune response to human immunodeficiency virus type 1 (HIV-1) by binding to the virus's viral infectivity factor (Vif) protein. Sp140 contains a nuclear localization signal, a dimerization domain (HSR or CARD domain), a SAND domain, a PHD finger, and a BRD.