Nek1 shares structural and functional similarities with NIMA kinase.
The Aspergillus NIMA serine/threonine kinase plays a pivotal role in controlling entrance into mitosis. A major function attributed to NIMA is the induction of chromatin condensation. We show here that the founder murine NIMA-related kinase, Nek1, is larger than previously reported, and that the full-length protein conserves the structural hallmarks of NIMA. Even though Nek1 bears two classical nuclear localization signals (NLS), the endogenous protein localizes to the cytoplasm. Ectopic overexpression of various Nek1 constructs suggests that the C-terminus of Nek1 bears cytoplasmic localization signal(s). Overexpression of nuclear constructs of Nek1 resulted in abnormal chromatin condensation, with the DNA mainly confined to the periphery of the nucleus. Advanced condensation phenotype was associated with nuclear pore complex dispersal. The condensation was not accompanied by up-regulation of mitotic or apoptotic markers. A similar phenotype has been described following NIMA overexpression, strengthening the notion that the mammalian Nek1 kinase has functional similarity to NIMA.
Feige
Erez
E
Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
Shalom
Ohad
O
Tsuriel
Shlomo
S
Yissachar
Nissan
N
Motro
Benny
B
D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D015870:Gene Expression; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D000072380:NIMA-Related Kinase 1; D010768:Phosphoserine; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D018797:Cell Cycle Proteins; D002843:Chromatin; D006657:Histones; D010768:Phosphoserine; D011505:Protein-Tyrosine Kinases; C000606914:NEK1 protein, human; D000072380:NIMA-Related Kinase 1; C000606920:Nek1 protein, mouse; D017346:Protein Serine-Threonine Kinases