Domain-specific interactions of human HP1-type chromodomain proteins and inner nuclear membrane protein LBR

J Biol Chem. 1997 Jun 6;272(23):14983-9. doi: 10.1074/jbc.272.23.14983.

Abstract

HP1-type chromodomain proteins self-associate as well as interact with the inner nuclear membrane protein LBR (lamin B receptor) and transcriptional coactivators TIF1alpha and TIF1beta. The domains of these proteins that mediate their various interactions have not been entirely defined. HP1-type proteins are predicted by hydrophobic cluster analysis to consist of two homologous but distinct globular domains, corresponding to the chromodomain and chromo shadow domain, separated by a hinge region. We show here that the chromo shadow domain mediates the self-associations of HP1-type proteins and is also necessary for binding to LBR both in vitro and in the yeast two-hybrid assay. Hydrophobic cluster analysis also predicts that the nucleoplasmic amino-terminal portion of LBR contains two globular domains separated by a hinge region. The interactions of the LBR domains with an HP1-type protein were also analyzed by the yeast two-hybrid and in vitro binding assays, which showed that a portion of the second globular domain is necessary for binding. The modular domain organization of HP1-type proteins and LBR can explain some of the diverse protein-protein interactions at the chromatin-lamina-membrane interface of the nuclear envelope.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Chromobox Protein Homolog 5
  • Chromosomal Proteins, Non-Histone / chemistry*
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Cloning, Molecular
  • HeLa Cells
  • Humans
  • Lamin B Receptor
  • Molecular Sequence Data
  • Nuclear Envelope / metabolism
  • Protein Conformation*
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism

Substances

  • Chromosomal Proteins, Non-Histone
  • Receptors, Cytoplasmic and Nuclear
  • Recombinant Fusion Proteins
  • Chromobox Protein Homolog 5