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. Interacts (via C-terminus) with CREBBP. Interacts with EGR2 (By similarity). 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. Shuttles between the nucleus and the cytoplasm by a nuclear export signal and (NES) in a CRM1-dependent manner. Expressed only in melanocytes and testis. Up-regulated by GPR39 in neuronal cells. Phosphorylated. Phosphorylation changes in a cell cycle-dependent manner and reduces its transcriptional coactivator activity. Belongs to the CITED family.