Structure and regulation of the human Nek2 centrosomal kinase.
The dimeric Ser/Thr kinase Nek2 regulates centrosome cohesion and separation through phosphorylation of structural components of the centrosome, and aberrant regulation of Nek2 activity can lead to aneuploid defects characteristic of cancer cells. Mutational analysis of autophosphorylation sites within the kinase domain identified by mass spectrometry shows a complex pattern of positive and negative regulatory effects on kinase activity that are correlated with effects on centrosomal splitting efficiency in vivo. The 2.2-A resolution x-ray structure of the Nek2 kinase domain in complex with a pyrrole-indolinone inhibitor reveals an inhibitory helical motif within the activation loop. This helix presents a steric barrier to formation of the active enzyme and generates a surface that may be exploitable in the design of specific inhibitors that selectively target the inactive state. Comparison of this "auto-inhibitory" conformation with similar arrangements in cyclin-dependent kinase 2 and epidermal growth factor receptor kinase suggests a role for dimerization-dependent allosteric regulation that combines with autophosphorylation and protein phosphatase 1c phosphatase activity to generate the precise spatial and temporal control required for Nek2 function in centrosomal maturation.
Rellos
Peter
P
Structural Genomics Consortium, Botnar Research Centre, University of Oxford, Oxford OX3 7LD, United Kingdom.
Ivins
Frank J
FJ
Baxter
Joanne E
JE
Pike
Ashley
A
Nott
Timothy J
TJ
Parkinson
Donna-Marie
DM
Das
Sanjan
S
Howell
Steven
S
Fedorov
Oleg
O
Shen
Qi Yu
QY
Fry
Andrew M
AM
Knapp
Stefan
S
Smerdon
Stephen J
SJ
D000494:Allosteric Regulation; D001665:Binding Sites; D018385:Centrosome / Q000201:enzymology*; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D019281:Dimerization; D006801:Humans; D013058:Mass Spectrometry; D000072379:NIMA-Related Kinases; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry*
C089441:NEK2 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases