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An autoinhibitory tyrosine motif in the cell-cycle-regulated Nek7 kinase is released through binding of Nek9.

Richards MW, O'Regan L, Mas-Droux C, Blot JM, Cheung J, Hoelder S, Fry AM, Bayliss R - Mol. Cell (2009)

Bottom Line: Tyrosine mutants of Nek7 and the related kinase Nek6 are constitutively active.The activity of Nek6 and Nek7, but not the tyrosine mutant, is increased by interaction with the Nek9 noncatalytic C-terminal domain, suggesting a mechanism in which the tyrosine is released from its autoinhibitory position.The autoinhibitory conformation is common to three Neks and provides a potential target for selective kinase inhibitors.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cancer Research, London, UK.

ABSTRACT
Mitosis is controlled by multiple protein kinases, many of which are abnormally expressed in human cancers. Nek2, Nek6, Nek7, and Nek9 are NIMA-related kinases essential for proper mitotic progression. We determined the atomic structure of Nek7 and discovered an autoinhibited conformation that suggests a regulatory mechanism not previously described in kinases. Additionally, Nek2 adopts the same conformation when bound to a drug-like molecule. In both structures, a tyrosine side chain points into the active site, interacts with the activation loop, and blocks the alphaC helix. Tyrosine mutants of Nek7 and the related kinase Nek6 are constitutively active. The activity of Nek6 and Nek7, but not the tyrosine mutant, is increased by interaction with the Nek9 noncatalytic C-terminal domain, suggesting a mechanism in which the tyrosine is released from its autoinhibitory position. The autoinhibitory conformation is common to three Neks and provides a potential target for selective kinase inhibitors.

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Related in: MedlinePlus

The Crystal Structure of Nek7 Shows an Autoinhibited Conformation that Suggests a Regulatory Mechanism Not Previously Described in Kinases(A) Secondary structure and key residues mapped onto the protein sequence of Nek7. Disordered regions are marked with a dashed line, and ordered regions are marked with a solid line, black arrow, or white rectangle to indicate random coil, β strand, and α helix respectively. Lys63 and Glu82 are marked with red boxes, Leu86 and Leu111 with gray boxes, Tyr97 with a cyan box, and the DLG motif with a green box.(B) Overview of ADP-bound Nek7 structure in cartoon representation. The side chain of Tyr97 and the ADP ligand (magenta) are shown as spheres. The dashed box indicates the region magnified in (C).(C) Cartoon and stick representation of Tyr97 and its surrounding environment. The H-bond between Tyr97 and the backbone of Leu180 is shown as a dashed line.
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fig1: The Crystal Structure of Nek7 Shows an Autoinhibited Conformation that Suggests a Regulatory Mechanism Not Previously Described in Kinases(A) Secondary structure and key residues mapped onto the protein sequence of Nek7. Disordered regions are marked with a dashed line, and ordered regions are marked with a solid line, black arrow, or white rectangle to indicate random coil, β strand, and α helix respectively. Lys63 and Glu82 are marked with red boxes, Leu86 and Leu111 with gray boxes, Tyr97 with a cyan box, and the DLG motif with a green box.(B) Overview of ADP-bound Nek7 structure in cartoon representation. The side chain of Tyr97 and the ADP ligand (magenta) are shown as spheres. The dashed box indicates the region magnified in (C).(C) Cartoon and stick representation of Tyr97 and its surrounding environment. The H-bond between Tyr97 and the backbone of Leu180 is shown as a dashed line.

Mentions: We crystallized the apo-form, full-length (35 kDa) human Nek7 protein and determined the structure to 2.1 Å. We also soaked the apo-form crystals with ADP and determined the ADP-bound structure to 2.3 Å resolution. Both structures have excellent refinement and geometry statistics (Table 1). The protein structures exhibit the canonical bilobal fold and are virtually identical. Residues 20–300 were modeled, with the exception of the disordered activation loop (residues 181–198) and a small loop (residues 237–240) (Figure 1A). The Gly-rich loop was more ordered in the ADP-bound structure, consistent with an interaction with the ADP ligand. The overall conformation is that of an inactive kinase with the αC helix, DLG motif, and activation loop displaced from the usual configuration observed in active enzymes (Figures 1B and 1C).


An autoinhibitory tyrosine motif in the cell-cycle-regulated Nek7 kinase is released through binding of Nek9.

Richards MW, O'Regan L, Mas-Droux C, Blot JM, Cheung J, Hoelder S, Fry AM, Bayliss R - Mol. Cell (2009)

The Crystal Structure of Nek7 Shows an Autoinhibited Conformation that Suggests a Regulatory Mechanism Not Previously Described in Kinases(A) Secondary structure and key residues mapped onto the protein sequence of Nek7. Disordered regions are marked with a dashed line, and ordered regions are marked with a solid line, black arrow, or white rectangle to indicate random coil, β strand, and α helix respectively. Lys63 and Glu82 are marked with red boxes, Leu86 and Leu111 with gray boxes, Tyr97 with a cyan box, and the DLG motif with a green box.(B) Overview of ADP-bound Nek7 structure in cartoon representation. The side chain of Tyr97 and the ADP ligand (magenta) are shown as spheres. The dashed box indicates the region magnified in (C).(C) Cartoon and stick representation of Tyr97 and its surrounding environment. The H-bond between Tyr97 and the backbone of Leu180 is shown as a dashed line.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807034&req=5

fig1: The Crystal Structure of Nek7 Shows an Autoinhibited Conformation that Suggests a Regulatory Mechanism Not Previously Described in Kinases(A) Secondary structure and key residues mapped onto the protein sequence of Nek7. Disordered regions are marked with a dashed line, and ordered regions are marked with a solid line, black arrow, or white rectangle to indicate random coil, β strand, and α helix respectively. Lys63 and Glu82 are marked with red boxes, Leu86 and Leu111 with gray boxes, Tyr97 with a cyan box, and the DLG motif with a green box.(B) Overview of ADP-bound Nek7 structure in cartoon representation. The side chain of Tyr97 and the ADP ligand (magenta) are shown as spheres. The dashed box indicates the region magnified in (C).(C) Cartoon and stick representation of Tyr97 and its surrounding environment. The H-bond between Tyr97 and the backbone of Leu180 is shown as a dashed line.
Mentions: We crystallized the apo-form, full-length (35 kDa) human Nek7 protein and determined the structure to 2.1 Å. We also soaked the apo-form crystals with ADP and determined the ADP-bound structure to 2.3 Å resolution. Both structures have excellent refinement and geometry statistics (Table 1). The protein structures exhibit the canonical bilobal fold and are virtually identical. Residues 20–300 were modeled, with the exception of the disordered activation loop (residues 181–198) and a small loop (residues 237–240) (Figure 1A). The Gly-rich loop was more ordered in the ADP-bound structure, consistent with an interaction with the ADP ligand. The overall conformation is that of an inactive kinase with the αC helix, DLG motif, and activation loop displaced from the usual configuration observed in active enzymes (Figures 1B and 1C).

Bottom Line: Tyrosine mutants of Nek7 and the related kinase Nek6 are constitutively active.The activity of Nek6 and Nek7, but not the tyrosine mutant, is increased by interaction with the Nek9 noncatalytic C-terminal domain, suggesting a mechanism in which the tyrosine is released from its autoinhibitory position.The autoinhibitory conformation is common to three Neks and provides a potential target for selective kinase inhibitors.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cancer Research, London, UK.

ABSTRACT
Mitosis is controlled by multiple protein kinases, many of which are abnormally expressed in human cancers. Nek2, Nek6, Nek7, and Nek9 are NIMA-related kinases essential for proper mitotic progression. We determined the atomic structure of Nek7 and discovered an autoinhibited conformation that suggests a regulatory mechanism not previously described in kinases. Additionally, Nek2 adopts the same conformation when bound to a drug-like molecule. In both structures, a tyrosine side chain points into the active site, interacts with the activation loop, and blocks the alphaC helix. Tyrosine mutants of Nek7 and the related kinase Nek6 are constitutively active. The activity of Nek6 and Nek7, but not the tyrosine mutant, is increased by interaction with the Nek9 noncatalytic C-terminal domain, suggesting a mechanism in which the tyrosine is released from its autoinhibitory position. The autoinhibitory conformation is common to three Neks and provides a potential target for selective kinase inhibitors.

Show MeSH
Related in: MedlinePlus