title: CalpB modulates border cell migration in Drosophila egg chambers.
abstract: BACKGROUND
  Calpains are calcium regulated intracellular cysteine proteases implicated in a variety of physiological functions and pathological conditions. The Drosophila melanogaster genome contains only two genes, CalpA and CalpB coding for canonical, active calpain enzymes. The movement of the border cells in Drosophila egg chambers is a well characterized model of the eukaryotic cell migration. Using this genetically pliable model we can investigate the physiological role of calpains in cell motility.
  
  
  RESULTS
  We demonstrate at the whole organism level that CalpB is implicated in cell migration, while the structurally related CalpA paralog can not fulfill the same function. The downregulation of the CalpB gene by mutations or RNA interference results in a delayed migration of the border cells in Drosophila egg chambers. This phenotype is significantly enhanced when the focal adhesion complex genes encoding for α-PS2 integrin ( if), β-PS integrin (mys) and talin (rhea) are silenced. The reduction of CalpB activity diminishes the release of integrins from the rear end of the border cells. The delayed migration and the reduced integrin release phenotypes can be suppressed by expressing wild-type talin-head in the border cells but not talin-head(R367A), a mutant form which is not able to bind β-PS integrin. CalpB can cleave talin in vitro, and the two proteins coimmunoprecipitate from Drosophila extracts.
  
  
  CONCLUSIONS
  The physiological function of CalpB in border cell motility has been demonstrated in vivo. The genetic interaction between the CalpB and the if, mys, as well as rhea genes, the involvement of active talin head-domains in the process, and the fact that CalpB and talin interact with each other collectively suggest that the limited proteolytic cleavage of talin is one of the possible mechanisms through which CalpB regulates cell migration.
authors: Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Nagyerdei krt, 98, Debrecen H-4032, Hungary.
authors: Endre
authors: E
authors: Kókai
authors: Ferencz Sándor
authors: FS
authors: Páldy
authors: Kálmán
authors: K
authors: Somogyi
authors: Anil
authors: A
authors: Chougule
authors: Margit
authors: M
authors: Pál
authors: Éva
authors: É
authors: Kerekes
authors: Péter
authors: P
authors: Deák
authors: Péter
authors: P
authors: Friedrich
authors: Viktor
authors: V
authors: Dombrádi
authors: Géza
authors: G
authors: Ádám
mesh_terms: D000818:Animals; D002154:Calpain / Q000378:metabolism*; D002465:Cell Movement; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism; D016608:Talin / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D016608:Talin; C485092:CalpB protein, Drosophila; D002154:Calpain; C569839:calpain A, Drosophila