2. Academic Validation
  3. Phosphorylation-induced conformational dynamics in an intrinsically disordered protein and potential role in phenotypic heterogeneity

Phosphorylation-induced conformational dynamics in an intrinsically disordered protein and potential role in phenotypic heterogeneity

  • Proc Natl Acad Sci U S A. 2017 Mar 28;114(13):E2644-E2653. doi: 10.1073/pnas.1700082114.
Prakash Kulkarni 1,  Mohit Kumar Jolly 2,  Dongya Jia 2 3,  Steven M Mooney 4,  Ajay Bhargava 5,  Luciane T Kagohara 6,  Yihong Chen 7,  Pengyu Hao 8,  Yanan He 7,  Robert W Veltri 6,  Alexander Grishaev 7,  Keith Weninger 8,  Herbert Levine 9 10 11,  John Orban 1 12
Affiliations

Affiliations

  • 1 Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850; [email protected] [email protected] [email protected].
  • 2 Center for Theoretical Biological Physics, Rice University, Houston, TX 77005.
  • 3 Graduate Program in Systems, Synthetic and Physical Biology, Rice University, Houston, TX 77005.
  • 4 Department of Biology, University of Waterloo, Waterloo, ON Canada N2L 3G1.
  • 5 Shakti BioResearch, Woodbridge, CT 06525.
  • 6 Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD 21287.
  • 7 Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850.
  • 8 Department of Physics, North Carolina State University, Raleigh, NC 27695.
  • 9 Center for Theoretical Biological Physics, Rice University, Houston, TX 77005; [email protected] [email protected] [email protected].
  • 10 Department of Physics and Astronomy, Rice University, Houston, TX 77005.
  • 11 Department of Bioengineering, Rice University, Houston, TX 77005.
  • 12 Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742.
PMID: 28289210 DOI: 10.1073/pnas.1700082114
Abstract

Intrinsically disordered proteins (IDPs) that lack a unique 3D structure and comprise a large fraction of the human proteome play important roles in numerous cellular functions. Prostate-Associated Gene 4 (PAGE4) is an IDP that acts as a potentiator of the Activator Protein-1 (AP-1) transcription factor. Homeodomain-Interacting Protein Kinase 1 (HIPK1) phosphorylates PAGE4 at S9 and T51, but only T51 is critical for its activity. Here, we identify a second kinase, CDC-Like Kinase 2 (CLK2), which acts on PAGE4 and hyperphosphorylates it at multiple S/T residues, including S9 and T51. We demonstrate that HIPK1 is expressed in both androgen-dependent and androgen-independent prostate Cancer (PCa) cells, whereas CLK2 and PAGE4 are expressed only in androgen-dependent cells. Cell-based studies indicate that PAGE4 interaction with the two kinases leads to opposing functions. HIPK1-phosphorylated PAGE4 (HIPK1-PAGE4) potentiates c-Jun, whereas CLK2-phosphorylated PAGE4 (CLK2-PAGE4) attenuates c-Jun activity. Consistent with the cellular data, biophysical measurements (small-angle X-ray scattering, single-molecule fluorescence resonance energy transfer, and NMR) indicate that HIPK1-PAGE4 exhibits a relatively compact conformational ensemble that binds AP-1, whereas CLK2-PAGE4 is more expanded and resembles a random coil with diminished affinity for AP-1. Taken together, the results suggest that the phosphorylation-induced conformational dynamics of PAGE4 may play a role in modulating changes between PCa cell phenotypes. A mathematical model based on our experimental data demonstrates how differential phosphorylation of PAGE4 can lead to transitions between androgen-dependent and androgen-independent phenotypes by altering the AP-1/Androgen Receptor regulatory circuit in PCa cells.

Keywords

PAGE-4; androgen resistance; intrinsic disorder; phenotypic heterogeneity; prostate cancer.

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