Structure of the Rb C-terminal domain bound to E2F1-DP1: a mechanism for phosphorylation-induced E2F release

Cell. 2005 Dec 16;123(6):1093-106. doi: 10.1016/j.cell.2005.09.044.

Abstract

The retinoblastoma (Rb) protein negatively regulates the G1-S transition by binding to the E2F transcription factors, until cyclin-dependent kinases phosphorylate Rb, causing E2F release. The Rb pocket domain is necessary for E2F binding, but the Rb C-terminal domain (RbC) is also required for growth suppression. Here we demonstrate a high-affinity interaction between RbC and E2F-DP heterodimers shared by all Rb and E2F family members. The crystal structure of an RbC-E2F1-DP1 complex reveals an intertwined heterodimer in which the marked box domains of both E2F1 and DP1 contact RbC. We also demonstrate that phosphorylation of RbC at serines 788 and 795 destabilizes one set of RbC-E2F-DP interactions directly, while phosphorylation at threonines 821 and 826 induces an intramolecular interaction between RbC and the Rb pocket that destabilizes the remaining interactions indirectly. Our findings explain the requirement of RbC for high-affinity E2F binding and growth suppression and establish a mechanism for the regulation of Rb-E2F association by phosphorylation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites / genetics
  • Crystallography, X-Ray
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Dimerization
  • E2F Transcription Factors / genetics
  • E2F Transcription Factors / metabolism
  • E2F1 Transcription Factor / genetics
  • E2F1 Transcription Factor / metabolism*
  • Humans
  • Models, Biological
  • Models, Molecular
  • Molecular Sequence Data
  • Multiprotein Complexes / chemistry
  • Multiprotein Complexes / metabolism
  • Peptide Fragments / chemistry
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary / genetics
  • Protein Structure, Tertiary / physiology
  • Retinoblastoma Protein / chemistry
  • Retinoblastoma Protein / genetics
  • Retinoblastoma Protein / metabolism*
  • Retinoblastoma-Like Protein p107 / genetics
  • Retinoblastoma-Like Protein p107 / metabolism
  • Sequence Homology, Amino Acid
  • Serine / metabolism
  • Threonine / metabolism
  • Transcription Factor DP1 / genetics
  • Transcription Factor DP1 / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism

Substances

  • DNA-Binding Proteins
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • E2F1 protein, human
  • Multiprotein Complexes
  • Peptide Fragments
  • RBL1 protein, human
  • Retinoblastoma Protein
  • Retinoblastoma-Like Protein p107
  • TFDP1 protein, human
  • TFDP2 protein, human
  • Transcription Factor DP1
  • Transcription Factors
  • Threonine
  • Serine