SH3 domain-mediated binding of the Drk protein to Dos is an important step in signaling of Drosophila receptor tyrosine kinases.
Activation of the Sevenless (Sev) receptor tyrosine kinase (RTK) in the developing Drosophila eye is required for the specification of the R7 photoreceptor cell fate. Daughter of Sevenless (Dos), a putative multi-site adaptor protein, is a substrate of the Sev kinase and is known to associate with the tyrosine phosphatase Corkscrew (Csw). Binding of Csw to Dos depends on the Csw Src homology 2 (SH2) domains and is an essential step for signaling by the Sev RTK. Dos, however, lacks a recognizable phosphotyrosine interaction domain and it was previously unclear how it is recruited to the Sev receptor. Here it is shown that the SH2/SH3 domain adaptor protein Drk can provide this link. Drk binds with its SH2 domain to the autophosphorylated Sev receptor while the C-terminal SH3 domain is able to associate with Dos. The Drk SH3 domain binding motifs on Dos were mapped to two sites which do not conform the known Drk SH3 domain binding motif (PxxPxR) but instead have the consensus PxxxRxxKP. Mutational analysis in vitro and in vivo provided evidence that both Drk binding sites fulfil an important function in the context of Sev and Drosophila epidermal growth factor receptor mediated signaling processes.
Cancer Research UK, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK.
Stephan M
SM
Feller
Heike
H
Wecklein
Marc
M
Lewitzky
Eike
E
Kibler
Thomas
T
Raabe
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics; D004330:Drosophila / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005123:Eye / Q000254:growth & development / Q000378:metabolism; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017344:Genes, Insect; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D018909:src Homology Domains
D018076:DNA, Complementary; C100319:Dos protein, Drosophila; D029721:Drosophila Proteins; D005136:Eye Proteins; D008562:Membrane Glycoproteins; C080530:drk protein, Drosophila; D020794:Receptor Protein-Tyrosine Kinases; C056737:sev protein, Drosophila; C098692:Csw protein, Drosophila; D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor