title: EGFR controls IQGAP basolateral membrane localization and mitotic spindle orientation during epithelial morphogenesis.
abstract: Establishing the correct orientation of the mitotic spindle is an essential step in epithelial cell division in order to ensure that epithelial tubules form correctly during organ development and regeneration. While recent findings have identified some of the molecular mechanisms that underlie spindle orientation, many aspects of this process remain poorly understood. Here, we have used the 3D-MDCK model system to demonstrate a key role for a newly identified protein complex formed by IQGAP1 and the epithelial growth factor receptor (EGFR) in controlling the orientation of the mitotic spindle. IQGAP1 is a scaffolding protein that regulates many cellular pathways, from cell-cell adhesion to microtubule organization, and its localization in the basolateral membrane ensures correct spindle orientation. Through its IQ motifs, IQGAP1 binds to EGFR, which is responsible for maintaining IQGAP1 in the basolateral membrane domain. Silencing IQGAP1, or disrupting the basolateral localization of either IQGAP1 or EGFR, results in a non-polarized distribution of NuMA, mitotic spindle misorientation and defects in single lumen formation.
authors.affiliation: Centro de Biología Molecular Severo Ochoa Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Bañón-Rodríguez
authors.forename: Manuel
authors.initials: M
authors.lastname: Gálvez-Santisteban
authors.forename: Silvia
authors.initials: S
authors.lastname: Vergarajauregui
authors.forename: Minerva
authors.initials: M
authors.lastname: Bosch
authors.forename: Arantxa
authors.initials: A
authors.lastname: Borreguero-Pascual
authors.forename: Fernando
authors.initials: F
authors.lastname: Martín-Belmonte
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D016764:Cell Polarity / Q000502:physiology*; D002478:Cells, Cultured; D004285:Dogs; D004848:Epithelium / Q000254:growth & development* / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D009024:Morphogenesis / Q000235:genetics*; D054730:Protein Interaction Domains and Motifs; D008941:Spindle Apparatus / Q000502:physiology*; D014018:Tissue Distribution; D020703:ras GTPase-Activating Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: C101203:IQ motif containing GTPase activating protein 1; D020703:ras GTPase-Activating Proteins; D066246:ErbB Receptors