Cell Signaling Technology

Product Pathways - Nuclear Receptor Signaling

Phospho-SRC-3 (Thr24) Antibody #2979

Applications Reactivity Sensitivity MW (kDa) Source
W IF-IC H Endogenous 160 Rabbit

Applications Key:  W=Western Blotting  IF-IC=Immunofluorescence (Immunocytochemistry)
Reactivity Key:  H=Human
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-SRC-3 (Thr24) Antibody detects endogenous levels of SRC-3 protein only when phosphorylated on Thr24. This antibody does not cross-react with other family members.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to sequence surrounding Thr24 of the human SRC-3 protein. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of cell extracts from MCF-7 cells, untreated or stimulated with heregulin, using Phospho-SRC-3 (Thr24) Antibody (upper and middle) or SRC-3 (5E11) Rabbit mAb #2126 (lower). The middle blot was treated with calf intestinal phosphatase (CIP) before antibody probing.

IF-IC

IF-IC

Confocal immunofluorescent analysis of HeLa cells, either untreated (left) or λ-phosphatase treated (right), using Phospho-SRC-3 (Thr24) Antibody (green). Actin filaments have been labeled with DY-554 phalloidin (red).

Background

There are three members of the steroid receptor co-activator (SRC) family of proteins: SRC-1 (NCoA-1), SRC-2 (TIF2/GRIP1/NCoA-2), and SRC-3 (ACTR/pCIP/RAC3/TRAM-1/AIB1). All SRC family members share significant structural homology and function to stimulate transcription mediated by nuclear hormone receptors and other transcriptional activators such as Stat3, NF-κB, E2F1, and p53 (1-4). Two SRC proteins, SRC-1 and SRC-3, function as histone acetyltransferases (5,6). In addition, all three family members can recruit other histone acetyltransferases (CBP/p300, PCAF) and histone methyltransferases (PRMT1, CARM1) to target promoters and cooperate to enhance expression of many genes (5-8). The SRC proteins play important roles in multiple physiological processes including cell proliferation, cell survival, somatic cell growth, mammary gland development, female reproductive function, and vasoprotection (9). SRC-1 and SRC-3 are conduits for kinase-mediated growth factor signaling to the estrogen receptor and other transcriptional activators. Seven SRC-1 phosphorylation sites and six SRC-3 phosphorylation sites have been identified, which are induced by steroids, cytokines, and growth factors and involve multiple kinase signaling pathways (9-11). Research has shown that all three SRC family members are associated with increased activity of nuclear receptors in breast, prostate, and ovarian carcinomas. According to the literature, SRC-3 is frequently amplified or overexpressed in a number of cancers (12), and SRC-1/PAX3 and SRC-2/MYST3 translocations are found associated with rhabdomyosarcoma and acute myeloid leukemia, respectively (13,14).

Phosphorylation of Thr24 of SRC-3 proteins can be induced by stimulation with EGF. Phosphorylated SRC-3 translocates from the cytoplasm to the nucleus where it interacts with other transcription factors and steroid hormone receptors and regulates gene expression (15).

  1. Giraud, S. et al. (2002) J. Biol. Chem. 277, 8004-8011.
  2. Na, S.Y. et al. (1998) J. Biol. Chem. 273, 10831-10834.
  3. Louie, M.C. et al. (2004) Mol. Cell Biol. 24, 5157-5171.
  4. Lee, S.K. et al. (1999) Mol. Endocrinol. 13, 1924-1933.
  5. Spencer, T.E. et al. (1997) Nature 389, 194-198.
  6. Chen, H. et al. (1997) Cell 90, 569-580.
  7. Koh, S.S. et al. (2001) J. Biol. Chem. 276, 1089-1098.
  8. Chen, D. et al. (1999) Science 284, 2174-2177.
  9. Wu, R.C. et al. (2004) Mol. Cell 15, 937-949.
  10. Rowan, B.G. et al. (2000) J. Biol. Chem. 275, 4475-4483.
  11. Zhou, H.J. et al. (2005) Cancer Res. 65, 7976-7983.
  12. Torres-Arzayus, M.I. et al. (2004) Cancer Cell 6, 263-274.
  13. Wachtel, M. et al. (2004) Cancer Res. 64, 5539-5545.
  14. Deguchi, K. et al. (2003) Cancer Cell 3, 259-271.
  15. Amazit, L. et al. (2007) Mol. Cell Biol. 27, 6913-6932.

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