Abstract
Three protein kinase families, Aurora, Polo, and NIMA-related kinases (NEKs), regulate mitotic processes downstream from cyclin-dependent kinases. NEKs are highly conserved in eukaryotes and extended into multi-gene family. Previous studies in fungi and animals indicated that NEKs regulate mitotic progression, centrosomal separation, spindle formation, and cilia function, while functions of plant NEKs remain to be elucidated. Our recent work revealed that Arabidopsis NEK6 associates with cortical microtubules and modulates anisotropic cell growth and morphology interacting with armadillo-repeat kinesins (Sakai et al. 2008, Motose et al. 2008). Here, we describe functional analysis of NEKs in Arabidopsis with special emphasis on NEK6. NEK6 was highly accumulated in meristematic cells and associated with the cytokinetic phragmoplasts. NEK6 was concentrated in the dot-like structures exhibiting the dynamic movement along with the phragmoplasts and cortical microtubules. We also provide evidences for NEK-dependent microtubule regulation and functional relationship among NEKs.
