title: Src kinases mediate the interaction of the apical determinant Bazooka/PAR3 with STAT92E and increase signalling efficiency in Drosophila ectodermal cells.
abstract: Intercellular communication depends on the correct organization of the signal transduction complexes. In many signalling pathways, the mechanisms controlling the overall cell polarity also localize components of these pathways to different domains of the plasma membrane. In the Drosophila ectoderm, the JAK/STAT pathway components are highly polarized with apical localization of the receptor, the associated kinase and the STAT92E protein itself. The apical localization of STAT92E is independent of the receptor complex and is due to its direct association with the apical determining protein Bazooka (Baz). Here, we find that Baz-STAT92E interaction depends on the presence of the Drosophila Src kinases. In the absence of Src, STAT92E cannot bind to Baz in cells or in whole embryos, and this correlates with an impairment of JAK/STAT signalling function. We believe that the requirement of Src proteins for STAT92E apical localization is mediated through Baz, as we can co-precipitate Src with Baz but not with STAT92E. This is the first time that a functional link between cell polarity, the JAK/STAT signalling pathway and the Src kinases has been established in a whole organism.
authors: Centro Andaluz de Biología del Desarrollo, CSIC/JA/UPO, Ctra de Utrera Km1, 41013 Sevilla, Spain. ssotmar@upo.es
authors: Sol
authors: S
authors: Sotillos
authors: Michael
authors: M
authors: Krahn
authors: Jose Manuel
authors: JM
authors: Espinosa-Vázquez
authors: James Castelli-Gair
authors: JC
authors: Hombría
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics; D004330:Drosophila / Q000196:embryology / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D004475:Ectoderm / Q000196:embryology / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D005260:Female; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D053612:Janus Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008297:Male; D011485:Protein Binding / Q000235:genetics; D050791:STAT Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D050791:STAT Transcription Factors; C105675:Stat92E protein, Drosophila; D014157:Transcription Factors; C400774:baz protein, Drosophila; D053612:Janus Kinases; C085845:hop protein, Drosophila; D019061:src-Family Kinases