Structural basis of Aurora-A activation by TPX2 at the mitotic spindle.
Aurora-A is an oncogenic kinase essential for mitotic spindle assembly. It is activated by phosphorylation and by the microtubule-associated protein TPX2, which also localizes the kinase to spindle microtubules. We have uncovered the molecular mechanism of Aurora-A activation by determining crystal structures of its phosphorylated form both with and without a 43 residue long domain of TPX2 that we identified as fully functional for kinase activation and protection from dephosphorylation. In the absence of TPX2, the Aurora-A activation segment is in an inactive conformation, with the crucial phosphothreonine exposed and accessible for deactivation. Binding of TPX2 triggers no global conformational changes in the kinase but pulls on the activation segment, swinging the phosphothreonine into a buried position and locking the active conformation. The recognition between Aurora-A and TPX2 resembles that between the cAPK catalytic core and its flanking regions, suggesting this molecular mechanism may be a recurring theme in kinase regulation.
Structural and Computational Biology Programme, European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117, Heidelberg, Germany .
Richard
R
Bayliss
Teresa
T
Sardon
Isabelle
I
Vernos
Elena
E
Conti
D000595:Amino Acid Sequence / Q000502:physiology; D064127:Aurora Kinases; D001665:Binding Sites / Q000502:physiology; D020134:Catalytic Domain / Q000502:physiology; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000502:physiology*; D018360:Crystallography, X-Ray; D006367:HeLa Cells; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000502:physiology*; D008938:Mitosis / Q000502:physiology; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000502:physiology*; D009687:Nuclear Proteins / Q000737:chemistry* / Q000502:physiology*; D010750:Phosphoproteins / Q000737:chemistry* / Q000502:physiology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry*; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary / Q000502:physiology; D008941:Spindle Apparatus / Q000201:enzymology* / Q000502:physiology*; D013912:Threonine / Q000737:chemistry; D029867:Xenopus Proteins
D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; C122167:TPX2 protein, human; D029867:Xenopus Proteins; D013912:Threonine; D011494:Protein Kinases; C112134:AURKA protein, Xenopus; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases