NCOA1
Domain
The C-terminal (1107-1441) part mediates the histone acetyltransferase (HAT) activity.
Contains 7 Leu-Xaa-Xaa-Leu-Leu (LXXLL) motifs. LXXLL motifs 3, 4 and 5 are essential for the association with nuclear receptors. LXXLL motif 7, which is not present in isoform 2, increases the affinity for steroid receptors in vitro.
Function
Nuclear receptor coactivator that directly binds nuclear receptors and stimulates the transcriptional activities in a hormone-dependent fashion. Involved in the coactivation of different nuclear receptors, such as for steroids (PGR, GR and ER), retinoids (RXRs), thyroid hormone (TRs) and prostanoids (PPARs). Also involved in coactivation mediated by STAT3, STAT5A, STAT5B and STAT6 transcription factors. Displays histone acetyltransferase activity toward H3 and H4; the relevance of such activity remains however unclear. Plays a central role in creating multisubunit coactivator complexes that act via remodeling of chromatin, and possibly acts by participating in both chromatin remodeling and recruitment of general transcription factors. Required with NCOA2 to control energy balance between white and brown adipose tissues. Required for mediating steroid hormone response. Isoform 2 has a higher thyroid hormone-dependent transactivation activity than isoform 1 and isoform 3.
Involvement in disease
A chromosomal aberration involving NCOA1 is a cause of rhabdomyosarcoma. Translocation t(2;2)(q35;p23) with PAX3 generates the NCOA1-PAX3 oncogene consisting of the N-terminus part of PAX3 and the C-terminus part of NCOA1. The fusion protein acts as a transcriptional activator. Rhabdomyosarcoma is the most common soft tissue carcinoma in childhood, representing 5-8% of all malignancies in children.
Post-translational modifications
Sumoylated; sumoylation increases its interaction with PGR and prolongs its retention in the nucleus. It does not prevent its ubiquitination and does not exert a clear effect on the stability of the protein.
Ubiquitinated; leading to proteasome-mediated degradation. Ubiquitination and sumoylation take place at different sites.
Sequence Similarities
Belongs to the SRC/p160 nuclear receptor coactivator family.
Tissue Specificity
Widely expressed.
Cellular localization
- Nucleus
Alternative names
BHLHE74, SRC1, NCOA1, Nuclear receptor coactivator 1, NCoA-1, Class E basic helix-loop-helix protein 74, Protein Hin-2, RIP160, Renal carcinoma antigen NY-REN-52, Steroid receptor coactivator 1, bHLHe74, SRC-1