2. Academic Validation
  3. The Stress-response protein prostate-associated gene 4, interacts with c-Jun and potentiates its transactivation

The Stress-response protein prostate-associated gene 4, interacts with c-Jun and potentiates its transactivation

  • Biochim Biophys Acta. 2014 Feb;1842(2):154-63. doi: 10.1016/j.bbadis.2013.11.014.
Krithika Rajagopalan 1,  Ruoyi Qiu 2,  Steven M Mooney 1,  Shweta Rao 1,  Takumi Shiraishi 1,  Elizabeth Sacho 2,  Hongying Huang 3,  Ellen Shapiro 3,  Keith R Weninger 4,  Prakash Kulkarni 5
Affiliations

Affiliations

  • 1 Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
  • 2 Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
  • 3 Department of Urology, New York University School of Medicine, New York, NY 10016, USA.
  • 4 Department of Physics, North Carolina State University, Raleigh, NC 27695, USA. Electronic address: krwening@ncsu.edu.
  • 5 Department of Urology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. Electronic address: pkulkar4@jhmi.edu.
PMID: 24263171 DOI: 10.1016/j.bbadis.2013.11.014
Abstract

The Cancer/Testis Antigen (CTA), Prostate-associated Gene 4 (PAGE4), is a stress-response protein that is upregulated in prostate Cancer (PCa) especially in precursor lesions that result from inflammatory stress. In cells under stress, translocation of PAGE4 to mitochondria increases while production of Reactive Oxygen Species decreases. Furthermore, PAGE4 is also upregulated in human fetal prostate, underscoring its potential role in development. However, the proteins that interact with PAGE4 and the mechanisms underlying its pleiotropic functions in prostatic development and disease remain unknown. Here, we identified c-Jun as a PAGE4 interacting partner. We show that both PAGE4 and c-Jun are overexpressed in the human fetal prostate; and in cell-based assays, PAGE4 robustly potentiates c-Jun transactivation. Single-molecule Förster resonance energy transfer experiments indicate that upon binding to c-Jun, PAGE4 undergoes conformational changes. However, no interaction is observed in presence of BSA or unilamellar vesicles containing the mitochondrial inner membrane diphosphatidylglycerol lipid marker cardiolipin. Together, our data indicate that PAGE4 specifically interacts with c-Jun and that, conformational dynamics may account for its observed pleiotropic functions. To our knowledge, this is the first report demonstrating crosstalk between a CTA and a proto-oncogene. Disrupting PAGE4/c-Jun interactions using small molecules may represent a novel therapeutic strategy for PCa.

Keywords

BPH; BSA; CD; Cancer/Testis Antigen; DBD; DLS; DMSO; DNA-binding domain; Dimethyl sulfoxide; IPTG; Intrinsically disordered protein; Isopropyl 1-thio-β-d-galactopyranoside; NMR; PAGE4; PBS; PC; PCa; PE; PIA; PIN; PINs; PVP; Phosphate Buffered Saline; Prostate Associated Gene 4; Prostate cancer; QY; SDS-PAGE; SEC; Sodium Dodecyl sulfate poly-acrylamide gel electrophoresis; TCEP·HCl; Tris(2-carboxyethyl)phosphine hydrochloride; benign prostatic hyperplasia; bovine serum albumin; c-Jun; circular dichroism; dynamic light scattering; nuclear magnetic resonance; phosphatidylcholine; phosphatidylethanolamine; polyvinyl pyrollidone; proliferative inflammatory atrophy; prostate cancer; prostatic intraepithelial neoplasia; protein interaction networks; quantum yield; single-molecule Förster resonance energy transfer; size exclusion chromatography; smFRET.

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