The FERM-domain protein Expanded regulates Hippo pathway activity via direct interactions with the transcriptional activator Yorkie.
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.
Badouel
Caroline
C
Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, Toronto, ON M5G 1X5, Canada.
Gardano
Laura
L
Amin
Nancy
N
Garg
Ankush
A
Rosenfeld
Robyn
R
Le Bihan
Thierry
T
McNeill
Helen
H
D020816:Amino Acid Motifs; D000818:Animals; D030801:Animals, Genetically Modified; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D004330:Drosophila / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D000091102:YAP-Signaling Proteins; D000099317:Hippo Kinases
D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011994:Recombinant Proteins; D015534:Trans-Activators; D000091102:YAP-Signaling Proteins; C503814:Yki protein, Drosophila; C085090:ex protein, Drosophila; C093503:wts protein, Drosophila; C499474:hpo protein, Drosophila; D000099317:Hippo Kinases