Kinase interaction domain of kinase-associated protein phosphatase, a phosphoprotein-binding domain.
Kinase-associated protein phosphatase interacts specifically with plant receptor-like protein kinases. This interaction is thought to be a key step in signal perception and transduction. The minimal kinase interaction (KI) domain of kinase-associated protein phosphatase was mapped to a 119-aa segment spanning residues 180 to 298. A forkhead-associated (FHA) homology region resides in this minimal KI domain. Site-directed mutagenesis of four highly conserved sites in this FHA homology region abolishes the KI domain's interaction with receptor-like protein kinases, indicating that the FHA region is essential for binding. Serial deletion analysis indicates that 30 aa on each side of the FHA region are also needed for binding; this minimal functional unit is designated as the KI domain. Kinetic studies using surface plasmon resonance indicate that the binding between the KI domain and receptor-like protein kinases has a dissociation constant (KD) of about 25-100 nM, which is similar to the binding affinity of two other well characterized phosphorylation-dependent protein-binding domains (14-3-3 and Src homology 2) and their high-affinity phosphopeptide ligands.
Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO 65211, USA.
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J
Li
G P
GP
Smith
J C
JC
Walker
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology; D029681:Arabidopsis Proteins; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics; D017124:Conserved Sequence; D005982:Glutathione Transferase / Q000235:genetics; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D058619:Maltose-Binding Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D005982:Glutathione Transferase; C090240:KAPP protein, Arabidopsis; D010749:Phosphoprotein Phosphatases