Preparing your results

Our searching services are busy right now. Your search will reload in five seconds.

X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Regulation of SRC-3 intercompartmental dynamics by estrogen receptor and phosphorylation.

http://www.ncbi.nlm.nih.gov/pubmed/17646391

The steroid receptor coactivator 3 gene (SRC-3) (AIB1/ACTR/pCIP/RAC3/TRAM1) is a p160 family transcription coactivator and a known oncogene. Despite its importance, the functional regulation of SRC-3 remains poorly understood within a cellular context. Using a novel combination of live-cell, high-throughput, and fluorescent microscopy, we report SRC-3 to be a nucleocytoplasmic shuttling protein whose intracellular mobility, solubility, and cellular localization are regulated by phosphorylation and estrogen receptor alpha (ERalpha) interactions. We show that both chemical inhibition and small interfering RNA reduction of the mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2 (MEK1/2) pathway induce a cytoplasmic shift in SRC-3 localization, whereas stimulation by epidermal growth factor signaling enhances its nuclear localization by inducing phosphorylation at T24, S857, and S860, known participants in the phosphocode that regulates SRC-3 activity. Accordingly, the cytoplasmic localization of a nonphosphorylatable SRC-3 mutant further supported these results. In the presence of ERalpha, U0126 also dramatically reduces (i) ligand-dependent colocalization of SRC-3 and ERalpha, (ii) the formation of ER-SRC-3 complexes in cell lysates, and (iii) SRC-3 targeting to a visible, ERalpha-occupied and -regulated prolactin promoter array. Taken together, these results indicate that phosphorylation coordinates SRC-3 coactivator function by linking the probabilistic formation of transient nuclear receptor-coactivator complexes with its molecular dynamics and cellular compartmentalization. Technically and conceptually, these findings have a new and broad impact upon evaluating mechanisms of action of gene regulators at a cellular system level.

Pubmed ID: 17646391 RIS Download

Mesh terms: Active Transport, Cell Nucleus | Animals | Cell Line | Cell Nucleus | Cytoplasm | Endoplasmic Reticulum | Epidermal Growth Factor | Extracellular Signal-Regulated MAP Kinases | Histone Acetyltransferases | Humans | Immunohistochemistry | Nuclear Proteins | Nuclear Receptor Coactivator 3 | Phosphorylation | Promoter Regions, Genetic | RNA Interference | Receptors, Estrogen | Recombinant Fusion Proteins | Signal Transduction | Subcellular Fractions | Trans-Activators

Research resources used in this publication

None found

Research tools detected in this publication

None found

Data used in this publication

None found

Associated grants

  • Agency: NIDDK NIH HHS, Id: DK55622
  • Agency: NIDDK NIH HHS, Id: DK61589
  • Agency: NICHD NIH HHS, Id: HD08818
  • Agency: NCI NIH HHS, Id: P01 CA06425
  • Agency: NICHD NIH HHS, Id: U54 HD96008

Publication data is provided by the National Library of Medicine ® and PubMed ®. Data is retrieved from PubMed ® on a weekly schedule. For terms and conditions see the National Library of Medicine Terms and Conditions.