The FERM-domain protein Expanded regulates Hippo pathway activity via direct interactions with the transcriptional activator Yorkie

Dev Cell. 2009 Mar;16(3):411-20. doi: 10.1016/j.devcel.2009.01.010.

Abstract

The Hippo kinase pathway plays a central role in growth regulation and tumor suppression from flies to man. The Hippo/Mst kinase phosphorylates and activates the NDR family kinase Warts/Lats, which phosphorylates and inhibits the transcriptional activator Yorkie/YAP. Current models place the FERM-domain protein Expanded upstream of Hippo kinase in growth control. To understand how Expanded regulates Hippo pathway activity, we used affinity chromatography and mass spectrometry to identify Expanded-binding proteins. Surprisingly we find that Yorkie is the major Expanded-binding protein in Drosophila S2 cells. Expanded binds Yorkie at endogenous levels via WW-domain-PPxY interactions, independently of Yorkie phosphorylation at S168, which is critical for 14-3-3 binding. Expanded relocalizes Yorkie from the nucleus, abrogating its nuclear activity, and it can regulate growth downstream of warts in vivo. These data lead to a new model whereby Expanded functions downstream of Warts, in concert with 14-3-3 proteins to sequester Yorkie in the cytoplasm, inhibiting growth activity of the Hippo pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Animals
  • Animals, Genetically Modified
  • Cell Line
  • Cytoplasm / metabolism
  • Drosophila / genetics
  • Drosophila / metabolism
  • Drosophila Proteins / chemistry
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Models, Biological
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Binding
  • Protein Kinases / genetics
  • Protein Kinases / metabolism
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Deletion
  • Signal Transduction
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transfection

Substances

  • Drosophila Proteins
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Nuclear Proteins
  • Recombinant Proteins
  • Trans-Activators
  • Yki protein, Drosophila
  • ex protein, Drosophila
  • Protein Kinases
  • wts protein, Drosophila
  • Protein-Serine-Threonine Kinases
  • hpo protein, Drosophila