Nuclear receptors for steroids, thyroid hormones and retinoic acids are ligand-dependent transcription factors that activate transcription through specific DNA binding sites in their target genes. Several related transcriptional coactivators and corepressors have been described that work in concert with the steroid receptor family to either induce or repress transcription from hormone-responsive elements. This family includes GRIP1 (for GR interacting protein 1, also designated NCoA-2 or Tif2); SRC-1 (for steroid receptor coactivator-1, also designated NCoA-1); RAC3 (also designated AIB1, for amplified in breast cancer, or ACTR), which displays elevated expression in estrogen receptor positive ovarian and breast cancers; and p/CIP (for p300/CBP/Co-Integrator Protein), which is required for the transcriptional activation of p300/CBP-dependent transcription factors. The nuclear receptor coactivator 1 (NCOA1) is a transcriptional coregulatory protein that contains several nuclear receptor interacting domains and an intrinsic histone acetyltransferase activity. NCOA1 is recruited to DNA promotion sites by ligand-activated nuclear receptors. NCOA1, in turn, acylates histones, which makes downstream DNA more accessible to transcription. Hence, NCOA1 assists nuclear receptors in the upregulation of DNA expression. NCOA1 is also frequently called steroid receptor coactivator-1 (SRC-1).
Background References
1. Kalkhoven E et al. Isoforms of steroid receptor coactivator 1 differ in their ability to potentiate transcription by the oestrogen receptor. EMBO J 17:232-243 (1998).
2. Onate S A et al. Sequence and characterization of a coactivator for the steroid hormone receptor superfamily. Science 270:1354-1357 (1995).
Sequence Similarity
Belongs to the SRC/p160 nuclear receptor coactivator family.
Tissue Specificity
Widely expressed.
Post-translational Modification
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.
Western blot analysis of SRC1 on different lysates with Rabbit anti-SRC1 antibody (ET7107-44) at 1/2,000 dilution.
Lane 1: Raji cell lysate Lane 2: HeLa cell lysate Lane 3: 293T cell lysate
Lysates/proteins at 20 µg/Lane.
Predicted band size: 157 kDa Observed band size: 157 kDa
Exposure time: 1 minute; ECL: K1802;
4-20% SDS-PAGE gel.
Proteins were transferred to a PVDF membrane and blocked with 5% NFDM/TBST for 1 hour at room temperature. The primary antibody (ET7107-44) at 1/2,000 dilution was used in 5% NFDM/TBST at 4℃ overnight. Goat Anti-Rabbit IgG - HRP Secondary Antibody (HA1001) at 1/50,000 dilution was used for 1 hour at room temperature.
Immunocytochemistry analysis of 293T cells labeling SRC1 with Rabbit anti-SRC1 antibody (ET7107-44) at 1/100 dilution.
Cells were fixed in 4% paraformaldehyde for 15 minutes at room temperature, permeabilized with 0.1% Triton X-100 in PBS for 15 minutes at room temperature, then blocked with 1% BSA in 10% negative goat serum for 1 hour at room temperature. Cells were then incubated with Rabbit anti-SRC1 antibody (ET7107-44) at 1/100 dilution in 1% BSA in PBST overnight at 4 ℃. Goat Anti-Rabbit IgG H&L (iFluor™ 488, HA1121) was used as the secondary antibody at 1/1,000 dilution. PBS instead of the primary antibody was used as the secondary antibody only control. Nuclear DNA was labelled in blue with DAPI.
Beta tubulin (HA601187, red) was stained at 1/100 dilution overnight at +4℃. Goat Anti-Mouse IgG H&L (iFluor™ 594, HA1126) was used as the secondary antibody at 1/1,000 dilution.
Immunohistochemical analysis of paraffin-embedded human breast cancer tissue with Rabbit anti-SRC1 antibody (ET7107-44) at 1/1,000 dilution.
The section was pre-treated using heat mediated antigen retrieval with sodium citrate buffer (pH 6.0) (high pressure) for 2 minutes. The tissues were blocked in 1% BSA for 20 minutes at room temperature, washed with ddH2O and PBS, and then probed with the primary antibody (ET7107-44) at 1/1,000 dilution for 1 hour at room temperature. The detection was performed using an HRP conjugated compact polymer system. DAB was used as the chromogen. Tissues were counterstained with hematoxylin and mounted with DPX.
Please note: All products are "FOR RESEARCH USE ONLY AND ARE NOT INTENDED FOR DIAGNOSTIC OR THERAPEUTIC USE"