serine/threonine protein kinase Nek9; nercc1 kinase; never in mitosis A-related kinase 9; NimA-related protein kinase 9 (NEK9, KIAA1995, NERCC)

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Function

pleiotropic regulator of mitotic progression, participating in the control of spindle dynamics & chromosome separation
phosphorylates different histones, myelin basic protein, beta-casein, & BICD2
phosphorylates histone H3 on Ser & Thr & beta-casein on Ser
important for G1/S transition & S phase progression
phosphorylates NEK6 & NEK7 & stimulates their activity by releasing the autoinhibitory functions of Tyr-108 & Tyr-97 respectively
activated during mitosis by intramolecular autophosphorylation
activity & autophosphorylation is activated by Mn+2 >> Mg+2
sensitive to increasing concentration of detergents
not cell-cycle regulated but activity is higher in G0-arrested cells
autophosphorylated on Ser & Thr
when complexed with FACT, exhibits markedly elevated phosphorylation on Thr-210
during mitosis, not phosphorylated on Thr-210
phosphorylated by CDK1 in vitro
binds to Ran GTPase
has a greater affinity for Ran-GDP over Ran-GTP
interacts with NEK6, NEK7 & BICD2
interacts with SSRP1 & SUPT16H, the 2 subunits of the FACT complex

homodimer
dimerizes through its coiled-coil domain
belongs to the protein kinase superfamily, NEK Ser/Thr protein kinase family, NIMA subfamily
contains 1 protein kinase domain
contains 6 RCC1 repeats

highest expression in heart, liver, kidney & testis
also expressed in smooth muscle cells & fibroblasts
expression varied mildly across the cell cycle
- highest expression in G1 & stationary-phase cells