Structure of a beta-TrCP1-Skp1-beta-catenin complex: destruction motif binding and lysine specificity of the SCF(beta-TrCP1) ubiquitin ligase.
The SCF ubiquitin ligases catalyze protein ubiquitination in diverse cellular processes. SCFs bind substrates through the interchangeable F box protein subunit, with the >70 human F box proteins allowing the recognition of a wide range of substrates. The F box protein beta-TrCP1 recognizes the doubly phosphorylated DpSGphiXpS destruction motif, present in beta-catenin and IkappaB, and directs the SCF(beta-TrCP1) to ubiquitinate these proteins at specific lysines. The 3.0 A structure of a beta-TrCP1-Skp1-beta-catenin complex reveals the basis of substrate recognition by the beta-TrCP1 WD40 domain. The structure, together with the previous SCF(Skp2) structure, leads to the model of SCF catalyzing ubiquitination by increasing the effective concentration of the substrate lysine at the E2 active site. The model's prediction that the lysine-destruction motif spacing is a determinant of ubiquitination efficiency is confirmed by measuring ubiquitination rates of mutant beta-catenin peptides, solidifying the model and also providing a mechanistic basis for lysine selection.
Wu
Geng
G
Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Xu
Guozhou
G
Schulman
Brenda A
BA
Jeffrey
Philip D
PD
Harper
J Wade
JW
Pavletich
Nikola P
NP
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000737:chemistry*; D016384:Consensus Sequence; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D044786:S-Phase Kinase-Associated Proteins; D013379:Substrate Specificity; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*; D051176:beta Catenin; D044844:beta-Transducin Repeat-Containing Proteins
C471644:BTRC protein, human; C495270:CTNNB1 protein, human; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D010455:Peptides; D044786:S-Phase Kinase-Associated Proteins; D015534:Trans-Activators; D025801:Ubiquitin; D051176:beta Catenin; D044844:beta-Transducin Repeat-Containing Proteins; D019204:GTP-Binding Proteins; D008025:Ligases; D008239:Lysine