title: Integrins are required for cardioblast polarisation in Drosophila.
abstract: BACKGROUND
  The formation of a tubular organ, such as the heart, requires the communication of positional and polarity signals between migratory cells. Key to this process is the establishment of a new luminal domain on the cell surface, generally from the apical domain of a migratory cell. This domain will also acquire basal properties, as it will produce a luminal extracellular matrix. Integrin receptors are the primary means of cell adhesion and adhesion signaling with the extracellular matrix. Here we characterise the requirement of Integrins in a genetic model of vasculogenesis, the formation of the heart in Drosophila.
  
  
  RESULTS
  As with vertebrates, the Drosophila heart arises from lateral mesoderm that migrates medially to meet their contralateral partners, to then assemble a midline vessel. During migration, Integrins are among the first proteins restricted to the presumptive luminal domain of cardioblasts. Integrins are required for normal levels of leading edge membrane motility. Apical accumulation of Integrins is enhanced by Robo, and reciprocally, apicalisation of luminal factors like Slit and Robo requires Integrin function. Integrins may provide a template for the formation of a lumen by stabilising lumen factors like Robo. Subsequent to migration, Integrin is required for normal cardioblast alignment and lumen formation. This phenotype is most readily modified by other mutations that affect adhesion, such as Talin and extracellular matrix ligands.
  
  
  CONCLUSIONS
  Our findings reveal an instructive role for Integrins in communicating polarising information to cells during migration, and during transition to an epithelial tube structure.
authors.affiliation: Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada.
authors.forename: Jessica
authors.initials: J
authors.lastname: Vanderploeg
authors.forename: L Lourdes
authors.initials: LL
authors.lastname: Vazquez Paz
authors.forename: Allison
authors.initials: A
authors.lastname: MacMullin
authors.forename: J Roger
authors.initials: JR
authors.lastname: Jacobs
mesh_terms: D000818:Animals; D002465:Cell Movement; D016764:Cell Polarity; D029721:Drosophila Proteins / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D053263:Gene Regulatory Networks; D006321:Heart / Q000196:embryology*; D039001:Integrin alpha Chains / Q000378:metabolism / Q000502:physiology*; D032386:Myoblasts, Cardiac / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D021381:Protein Transport; D011971:Receptors, Immunologic / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D000097905:Roundabout Proteins
chemical_list: D029721:Drosophila Proteins; D016326:Extracellular Matrix Proteins; D039001:Integrin alpha Chains; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; D000097905:Roundabout Proteins; C572269:alpha PS3 integrin, Drosophila; C082188:if protein, Drosophila