title: Phosphorylation of the Hippo Pathway Component AMOTL2 by the mTORC2 Kinase Promotes YAP Signaling, Resulting in Enhanced Glioblastoma Growth and Invasiveness.
abstract: The mechanistic target of rapamycin (mTOR) and Hippo signaling pathways are two major signaling cascades that coordinately regulate cell growth and proliferation. Dysregulation of these pathways plays a critical role in gliomagenesis. Recent reports have provided evidence of cross-talk between the mTOR and Hippo pathways; however, a complete description of the signaling relationships between these pathways remains to be elucidated. Utilizing a gene-trapping strategy in a mouse glioma model, we report the identification of AMOTL2 as a candidate substrate for mTORC2. AMOTL2 is phosphorylated at serine 760 by mTORC2. Mutation of AMOTL2 mimicking constitutive Ser(760) phosphorylation blocks its ability to bind and repress YAP leading to increased relative expression of known YAP gene targets. Moreover, overexpression of AMOTL2 or a nonphosphorylatable AMOTL2-S760A mutant inhibited YAP-induced transcription, foci formation, growth, and metastatic properties, whereas overexpression of a phosphomimetic AMOTL2-S760E mutant negated these repressive effects of AMOTL2 in glioblastoma (GBM) cells in vitro. Similar effects on xenograft growth were observed in GBM cells expressing these AMOTL2 Ser(760) mutants. YAP was also shown to be required for Rictor-mediated GBM growth and survival. Finally, an analysis of mTORC2/AMOTL2/YAP activities in primary GBM samples supported the clinical relevance of this signaling cascade, and we propose that pharmacological agents cotargeting these regulatory circuits may hold therapeutic potential.
authors.affiliation: From the Department of Medicine, David Geffen School of Medicine at UCLA, the Department of Research and Development, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California 91343.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Artinian
authors.affiliation: the Department of Research and Development, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California 91343.
authors.forename: Cheri
authors.initials: C
authors.lastname: Cloninger
authors.affiliation: the Department of Research and Development, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California 91343.
authors.forename: Brent
authors.initials: B
authors.lastname: Holmes
authors.affiliation: the Department of Research and Development, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California 91343.
authors.forename: Angelica
authors.initials: A
authors.lastname: Benavides-Serrato
authors.affiliation: From the Department of Medicine, David Geffen School of Medicine at UCLA, the Department of Research and Development, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California 91343.
authors.forename: Tariq
authors.initials: T
authors.lastname: Bashir
authors.affiliation: From the Department of Medicine, David Geffen School of Medicine at UCLA, the Department of Research and Development, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, California 91343 Jonnson Comprehensive Cancer Center, and Molecular Biology Institute, UCLA, Los Angeles, California 90048 and jgera@mednet.ucla.edu.
authors.forename: Joseph
authors.initials: J
authors.lastname: Gera
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000091082:Angiomotins; D000818:Animals; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D000076225:Mechanistic Target of Rapamycin Complex 2; D051379:Mice; D008822:Mice, Transgenic; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D000076226:Rapamycin-Insensitive Companion of mTOR Protein; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014183:Transplantation, Heterologous; D000091102:YAP-Signaling Proteins
chemical_list: C508566:AMOTL2 protein, human; D048868:Adaptor Proteins, Signal Transducing; D000091082:Angiomotins; D002352:Carrier Proteins; D046912:Multiprotein Complexes; D010750:Phosphoproteins; C492571:RICTOR protein, human; D000076226:Rapamycin-Insensitive Companion of mTOR Protein; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human; D000076225:Mechanistic Target of Rapamycin Complex 2; D058570:TOR Serine-Threonine Kinases
keywords: AMOTL2; Hippo pathway; glioblastoma; mTOR complex (mTORC); mTORC2; mechanistic target of rapamycin (mTOR); yes-associated protein (YAP)