title: The Drosophila Mst ortholog, hippo, restricts growth and cell proliferation and promotes apoptosis.
abstract: Establishing and maintaining homeostasis is critical to the well-being of an organism and is determined by the balance of cell proliferation and death. Two genes that function together to regulate growth, proliferation, and apoptosis in Drosophila are warts (wts), encoding a serine/threonine kinase, and salvador (sav), encoding a WW domain containing Wts-interacting protein. However, the mechanisms by which sav and wts regulate growth and apoptosis are not well understood. Here, we describe mutations in hippo (hpo), which encodes a protein kinase most related to mammalian Mst1 and Mst2. Like wts and sav, hpo mutations result in increased tissue growth and impaired apoptosis characterized by elevated levels of the cell cycle regulator cyclin E and apoptosis inhibitor DIAP1. Hpo, Sav, and Wts interact physically and functionally, and regulate DIAP1 levels, likely by Hpo-mediated phosphorylation and subsequent degradation. Thus, Hpo links Sav and Wts to a key regulator of apoptosis.
authors.affiliation: Massachusetts General Hospital Cancer Center, Building 149, 13th Street, Charlestown, MA 02129, USA.
authors.forename: Kieran F
authors.initials: KF
authors.lastname: Harvey
authors.forename: Cathie M
authors.initials: CM
authors.lastname: Pfleger
authors.forename: Iswar K
authors.initials: IK
authors.lastname: Hariharan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000196:embryology / Q000502:physiology*; D005260:Female; D006706:Homeostasis; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000378:metabolism; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D014921:Wings, Animal / Q000033:anatomy & histology; D000099317:Hippo Kinases
chemical_list: D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C111891:DIAP1 protein, Drosophila; C465504:sav protein, Drosophila; C092745:LATS1 protein, human; C093503:wts protein, Drosophila; C095566:STK4 protein, human; D000099317:Hippo Kinases; C499474:hpo protein, Drosophila; C078754:STE20 protein, S cerevisiae