Transcriptional coactivator of the p300/CBP-mediated transcription complex. Enhances SMAD-mediated transcription by strengthening the functional link between the DNA-binding SMAD transcription factors and the p300/CBP transcription coactivator complex. Stimulates estrogen-dependent transactivation activity mediated by estrogen receptors signaling; stabilizes the interaction of estrogen receptor ESR1 and histone acetyltransferase EP300. Positively regulates TGF-beta signaling through its association with the SMAD/p300/CBP-mediated transcriptional coactivator complex. Induces transcription from estrogen-responsive promoters and protection against cell death. Potentiates EGR2-mediated transcriptional activation activity from the ERBB2 promoter. Acts as an inhibitor of osteoblastic mineralization through a cAMP-dependent parathyroid hormone receptor signaling. May play a role in pigmentation of melanocytes. Associates with chromatin to the estrogen-responsive TGF-alpha promoter region in a estrogen-dependent manner. Homodimer. Binds to RBM14. Interacts (via N-terminus) with HSPA8; the interaction suppresses the association of CITED1 with p300/CBP and SMAD-mediated transcription transactivation. Interacts (via C-terminus) with TOX3 (via HGM box); the interaction increases estrogen-response element (ERE)-dependent transcription and protection against cell death. Interacts with ESR1; the interaction occurs in a estrogen-dependent manner (By similarity). Interacts (unphosphorylated form preferentially and via C-terminus) with EP300. Interacts (via C-terminus) with CREBBP. Interacts with EGR2. Shuttles between the nucleus and the cytoplasm by a nuclear export signal (NES) and in a CRM1-dependent manner. Expressed in calvarial osteoblasts. Expressed in nulliparous mammary epithelial cells; absent in pregnant mice and in lacting mammary glands. Also expressed in mammary tumors (at protein level). Expressed only in melanocytes and testis. Expressed at high levels in the strongly pigmented melanoma cells but at low levels in the weakly pigmented cells. Expressed in trophectoderm-derived cells of the placenta. Up-regulated by parathyroid hormone, forskolin and phorbol ester in osteoblasts. Phosphorylated. Phosphorylation changes in a cell cycle-dependent manner and reduces its transcriptional cofactor activity (By similarity). Mice die shortly after birth. Mice show an abnormal placental development; the spongiotrophoblast layer is irregular in shape and enlarged while the labyrinthine layer is reduced in size, the blood spaces within the labyrinthine are disrupted. Produces more mineralized bone nodules and deposited twice as much calcium in the matrix. Belongs to the CITED family.