Regulation of Nek6 functions by its SUMOylation on the K252residue

Nek6 belongs to NIMA1 (never in mitosis, gene A) related kinase, which was originally identified in Aspergillus nidulans as a serine/threonine kinase critical for cell cycle progression. We noticed that the putative SUMOylation site is localized on the K252 residue in 251FKsD254 of Nek6, based on the consensus sequence FKxE; where F represents L, I, V or F and x is any amino acid. We observed that the Nek6 SUMO mutant (K252R) has decreased protein kinase activity, nuclear speckle localization and protein stability, compared with that of the Nek6 wild type. However, the Nek6 SUMO mutant increased the cell survival rate of COS‐1 cells as determined by FACS analysis. Therefore, our data suggest that SUMOylation on the K252 residue of Nek6 is required for its normal functions, such as proper nuclear localization, kinase activity and protein stability, to control cell cycle.