Nuclear speckles and nucleoli targeting by PIP2-PDZ domain interactions

EMBO J. 2005 Jul 20;24(14):2556-65. doi: 10.1038/sj.emboj.7600722. Epub 2005 Jun 16.

Abstract

PDZ (Postsynaptic density protein, Disc large, Zona occludens) domains are protein-protein interaction modules that predominate in submembranous scaffolding proteins. Recently, we showed that the PDZ domains of syntenin-1 also interact with phosphatidylinositol 4,5-bisphosphate (PIP2) and that this interaction controls the recruitment of the protein to the plasma membrane. Here we evaluate the general importance of PIP2-PDZ domain interactions. We report that most PDZ proteins bind weakly to PIP2, but that syntenin-2, the closest homolog of syntenin-1, binds with high affinity to PIP2 via its PDZ domains. Surprisingly, these domains target syntenin-2 to nuclear PIP2 pools, in nuclear speckles and nucleoli. Targeting to these sites is abolished by treatments known to affect these PIP2 pools. Mutational and domain-swapping experiments indicate that high-affinity binding to PIP2 requires both PDZ domains of syntenin-2, but that its first PDZ domain contains the nuclear PIP2 targeting determinants. Depletion of syntenin-2 disrupts the nuclear speckles-PIP2 pattern and affects cell survival and cell division. These findings show that PIP2-PDZ domain interactions can directly contribute to subnuclear assembly processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / metabolism
  • Cell Division / physiology
  • Cell Line, Tumor
  • Cell Membrane / metabolism
  • Cell Nucleolus / metabolism*
  • Cell Nucleus / metabolism*
  • Cell Survival / physiology
  • Cells, Cultured
  • Humans
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Lipid Bilayers / metabolism
  • Membrane Proteins / metabolism
  • Nerve Tissue Proteins / metabolism*
  • Phosphatidylinositol 4,5-Diphosphate / metabolism*
  • Protein Interaction Mapping
  • Protein Structure, Tertiary
  • Syntenins
  • Time Factors

Substances

  • Carrier Proteins
  • Intracellular Signaling Peptides and Proteins
  • Lipid Bilayers
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Phosphatidylinositol 4,5-Diphosphate
  • SDCBP protein, human
  • SDCBP2 protein, human
  • Syntenins
  • postsynaptic density proteins