A multimeric complex and the nuclear targeting of the Drosophila Rel protein Dorsal.
The intracellular part of the Rel signal transduction pathway in Drosophila is encoded by Toll, tube, pelle, dorsal, and cactus, and it functions to form the dorsal-ventral axis in the Drosophila embryo. Upon activation of the transmembrane receptor Toll, Dorsal dissociates from its cytoplasmic inhibitor Cactus and enters the nucleus. Tube and Pelle are required to relay the signal from Toll to the Dorsal-Cactus complex. In a yeast two-hybrid assay, we found that both Tube and Pelle interact with Dorsal. We confirmed these interactions in an in vitro binding assay. Tube interacts with Dorsal via its C-terminal domain, whereas full-length Pelle is required for Dorsal binding. Tube and Pelle bind Dorsal in the N-terminal domain 1 of the Dorsal Rel homology region rather than at the Cactus binding site. Domain 1 has been found to be necessary for Dorsal nuclear targeting. Genetic experiments indicate that Tube-Dorsal interaction is necessary for normal signal transduction. We propose a model in which Tube, Pelle, Cactus, and Dorsal form a multimeric complex that represents an essential aspect of signal transduction.
Yang
J
J
Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08855, USA.
Steward
R
R
D000818:Animals; D002467:Cell Nucleus / Q000502:physiology; D004268:DNA-Binding Proteins / Q000502:physiology*; D004330:Drosophila / Q000196:embryology / Q000502:physiology*; D029721:Drosophila Proteins; D019476:Insect Proteins / Q000502:physiology; D008562:Membrane Glycoproteins / Q000502:physiology; D016328:NF-kappa B / Q000502:physiology; D009687:Nuclear Proteins / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D011956:Receptors, Cell Surface; D015398:Signal Transduction; D051193:Toll-Like Receptors; D014157:Transcription Factors / Q000502:physiology
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011956:Receptors, Cell Surface; C068721:Tl protein, Drosophila; D051193:Toll-Like Receptors; D014157:Transcription Factors; C062236:dl protein, Drosophila; C077938:cact protein, Drosophila; C079896:pll protein, Drosophila; D017346:Protein Serine-Threonine Kinases