title: The KRAB-associated co-repressor KAP-1 is a coiled-coil binding partner, substrate and activator of the c-Fes protein tyrosine kinase.
abstract: The c-Fes protein tyrosine kinase is implicated in the differentiation of a number of cell types including neuronal, endothelial and myeloid cells. Structurally, Fes consists of a unique N-terminal region, followed by SH2 (Src homology domain 2) and kinase domains. Two coiled-coil (CC) domains (CC1 and CC2) located within the unique N-terminal region are critical regulators of Fes activity in vivo and may function to recruit Fes activators and/or substrates. A yeast two-hybrid screen, utilizing a K-562 cell cDNA library and the Fes CC2 domain as bait, identified an interacting clone encoding the CC domain and B-box motifs (residues 114-357) of the transcriptional co-repressor KRAB-associated protein (KAP)-1. KAP-1(114-357) interacted with full-length Fes in yeast, and the KAP-1 CC domain was sufficient to bind the Fes N-terminal region in Sf-9 cells. Co-expression of Fes with full-length KAP-1 in human 293T cells stimulated Fes autophosphorylation and led to KAP-1 tyrosine phosphorylation. Association of endogenous Fes and KAP-1 was also observed in HL-60 myeloid leukaemia cells. Together, these data identify a novel Fes-KAP-1 interaction, and suggest a dual role for KAP-1 as both a Fes activator and downstream effector.
authors.affiliation: Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Delfino
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Shaffer
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Smithgall
mesh_terms: D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007313:Insecta; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051578:Proto-Oncogene Proteins c-fes / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D013379:Substrate Specificity; D000076183:Tripartite Motif-Containing Protein 28
chemical_list: D004268:DNA-Binding Proteins; D012097:Repressor Proteins; C101116:TRIM28 protein, human; D000076183:Tripartite Motif-Containing Protein 28; C496645:FES protein, human; D051578:Proto-Oncogene Proteins c-fes