An activity-dependent network of interactions links the Rel protein Dorsal with its cytoplasmic regulators.
A signaling pathway active on the ventral side of the Drosophila embryo defines dorsoventral polarity. A cell surface signal relayed by Toll, Tube and Pelle releases the Rel-related protein Dorsal from its cytoplasmic inhibitor Cactus; free Dorsal translocates into nuclei and directs expression of ventral fates. Using the yeast two-hybrid system and immunoprecipitation experiments, we define scaffolding and anchoring interactions among the pathway components. We show that Dorsal binds specifically to Tube, Pelle and Cactus, and that the protein kinase activity of Pelle differentially regulates its interactions with Dorsal and Tube. We also identify Drosophila Filamin as a potential adaptor linking the interaction network, via Tube, to the transmembrane receptor Toll.
Edwards
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Department of Molecular Biology and Oncology, UT Southwestern Medical Center, Dallas, Texas 75235-9148, USA.
Towb
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Wasserman
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D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000502:physiology; D017930:Genes, Reporter; D019476:Insect Proteins / Q000378:metabolism; D008954:Models, Biological; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000378:metabolism*; D010750:Phosphoproteins / Q000096:biosynthesis / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D001616:beta-Galactosidase / Q000096:biosynthesis
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C062236:dl protein, Drosophila; C084727:tub protein, Drosophila; C077938:cact protein, Drosophila; D011494:Protein Kinases; C079896:pll protein, Drosophila; D017346:Protein Serine-Threonine Kinases; D001616:beta-Galactosidase