CITED4 Background Information CITED4 (Cbp/p300-interacting transactivator, with Glu/Asp-rich carboxy-terminal domain, 4), also designated transcriptional coactivator 4, interacts via its C-terminus with the cysteine-histidine-rich domain 1 (CH1) of EP300 (p300) and CREB-binding protein (CBP). CITED4 may inhibit interaction of hypoxia-inducible factor 1 å (HIF-1å) with CBP, thus inhibiting transactivation by HIF1A. CITED4 also interacts as a transcriptional coactivator with all isoforms of TFAP2. Nuclear loss or cytoplasmic translocation of CITED4, followed by a loss of HIF-1å transcriptional antagonist activity, indicates breast cancer de-velopment. CITED4 expression occurs in a variety of tissues including heart, liver, skeletal muscle, pancreas and various breast cancer cell lines. CITED4 is highly expressed in embryonic endothelial cells mammary epithelial cells of pregnant and lactating females, respectively. Regulation of CITED4 may occur through the cell cycle.
