title: Molecular dissection of the interaction between the SH3 domain and the SH2-Kinase Linker region in PTK6.
abstract: PTK6 (also known as Brk) is an intracellular tyrosine kinase that contains SH3, SH2, and tyrosine kinase catalytic (Kinase) domains. The SH3 domain of PTK6 interacts with the N-terminal half of the linker (Linker) region between the SH2 and Kinase domains. Site-directed mutagenesis and surface plasmon resonance studies showed that a tryptophan residue (Trp44) in the SH3 domain and proline residues in the Linker region, in the order of Pro177, Pro175, and Pro179, contribute to the interaction. The three-dimensional modeled structure of the SH3-Linker complex was in agreement with the biochemical data. Disruption of the intramolecular interaction between the SH3 domain and the Linker region by mutation of Trp44, Pro175, Pro177, and Pro179 markedly increased the catalytic activity of PTK6 in HEK 293 cells. These results demonstrate that Trp44 in the SH3 domain and Pro177, Pro175, and Pro179 in the N-terminal half of the Linker region play important roles in the SH3-Linker interaction to maintain the protein in an inactive conformation along with the phosphorylated Tyr447-SH2 interaction.
authors.affiliation: Department of Biochemistry, College of Science, Yonsei University, Seoul 120-749, Republic of Korea.
authors.forename: Han Ie
authors.initials: HIe
authors.lastname: Kim
authors.forename: Jinwon
authors.initials: J
authors.lastname: Jung
authors.forename: Eun-Saem
authors.initials: ES
authors.lastname: Lee
authors.forename: Yong-Chul
authors.initials: YC
authors.lastname: Kim
authors.forename: Weontae
authors.initials: W
authors.lastname: Lee
authors.forename: Seung-Taek
authors.initials: ST
authors.lastname: Lee
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D003198:Computer Simulation; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D008956:Models, Chemical; D008958:Models, Molecular; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship; D018909:src Homology Domains / Q000502:physiology*