The synovial sarcoma translocation protein SYT-SSX2 recruits beta-catenin to the nucleus and associates with it in an active complex

Oncogene. 2006 Jun 22;25(26):3661-9. doi: 10.1038/sj.onc.1209413. Epub 2006 Feb 6.

Abstract

Localization of beta-catenin in the cell is a key determinant in its decision to function as a critical mediator of cell adhesion at the surface or a transcription activator in the nucleus. SYT-SSX2 is the fusion product of the chromosomal translocation, t(X;18)(p11.2;q11.2), which occurs in synovial sarcoma, a soft tissue tumor. SYT-SSX2 is known to associate with chromatin remodeling complexes and is proposed to be involved in controlling gene expression. We report that SYT-SSX2 plays a direct role in beta-catenin regulation. When expressed in mammalian cells, SYT-SSX2-induced beta-catenin recruitment to the nucleus. Interestingly, known target genes of canonical Wnt were not activated as a result of SYT-SSX2 expression, nor was the nuclear localization of beta-catenin due to one of the signaling pathways normally implicated in this event. beta-Catenin accumulation in the nucleus led to the formation of a transcriptionally active nuclear complex that contained SYT-SSX2 and beta-catenin. More importantly, depletion of SYT-SSX2 in primary synovial sarcoma cells resulted in loss of nuclear beta-catenin signal and a significant decrease in its signaling activity. These results unravel a novel pathway in the control of beta-catenin cellular transport and strongly suggest that SYT-SSX2 contributes to tumor development, in part through beta-catenin signaling.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism*
  • Cyclin D1 / metabolism
  • E1A-Associated p300 Protein / metabolism
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Mice
  • Multiprotein Complexes
  • Oncogene Proteins, Fusion / genetics
  • Oncogene Proteins, Fusion / metabolism*
  • Sarcoma, Synovial / genetics
  • Sarcoma, Synovial / metabolism
  • Signal Transduction / drug effects
  • Tumor Cells, Cultured
  • beta Catenin / genetics
  • beta Catenin / metabolism*

Substances

  • Enzyme Inhibitors
  • Multiprotein Complexes
  • Oncogene Proteins, Fusion
  • SYT-SSX fusion protein
  • beta Catenin
  • Cyclin D1
  • E1A-Associated p300 Protein