Nik Related Kinase (NRK)

NRK is a member of the GCK subfamily of protein kinases that are involved in activating the JNK pathway. The deduced 1,455-amino acid mouse protein contains an N-terminal Ste20-type catalytic domain, a coiled-coil region, 5 SH3 binding sites, and a C-terminal region that is conserved in the group I GCK subfamily, which includes NIK (MAP4K4).By whole-mount in situ hybridization, they demonstrated mouse Nrk expression in skeletal muscle during embryogenesis, with Nrk expression first observed in the ventral myotome at 10.5 days postcoitum. Northern blot analysis and semiquantitative PCR detected 8.0-kb Nrk transcript in mouse 11.5-day postcoitum embryos with increased expression from 15 to 17 days postcoitum.