The crystal structure of an inactive dimer of PDZ-binding kinase.
The overexpression of PDZ-binding kinase/T-LAK cell-originated protein kinase (PBK/TOPK) has been associated with hematologic tumors, breast cancer and various other cancers. However, the three-dimensional structure of PBK has not been solved. In this study, we determined the crystal structure of human PBK, which has two phospho-mimicking mutations T9E and T198E. The structural data indicated that PBK may assemble into an inactive dimer in alkaline conditions. Analytical size-exclusion chromatography and analytical ultracentrifugation confirmed that PBK exists in a conformational transition between dimers and monomers at different pH conditions. Co-IP and kinase assays suggested that the active state of PBK is a monomer and does not form a dimer even under alkaline conditions. These results showed that the conformational transition of PBK is important for its kinase activity regulation. Collectively, our observations may provide a novel starting point for structure-based functional studies.
College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
Chunming
C
Dong
College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
Xue
X
Tang
College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
Ying
Y
Xie
College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
Qingwei
Q
Zou
State Key Laboratory of Medicinal Chemical Biology, Nankai University, 94 Weijin Road, Tianjin 300071, China.
Xue
X
Yang
College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China; State Key Laboratory of Medicinal Chemical Biology, Nankai University, 94 Weijin Road, Tianjin 300071, China. Electronic address: haozhou@nankai.edu.cn.
Hao
H
Zhou
D019943:Amino Acid Substitution; D018360:Crystallography, X-Ray; D057809:HEK293 Cells; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D011994:Recombinant Proteins; D020929:Mitogen-Activated Protein Kinase Kinases; C409022:PDZ-binding kinase
Cancer; Inactive dimer; PBK/TOPK; X-ray crystal structure