Regulation Of Cep85 By Nek2 Kinase

The centrosome is the membraneless organelle possessed by most eukaryotic cells,and the main microtubule organization center in the cell.It is composed of a pair of centrioles and amorphous centromeric peripheral material(PCM).PCM is composed of hundreds of proteins,including structural proteins involved in microtubule nucleation and organization,as well as many important cell cycle regulators and signaling factors.How to organize these proteins in order to form a well-functioning centrosome is the current research hotspot and difficulty in this field.Cep85 is a PCM protein,located on the centrosome.Our previous research showed that it can regulate the activity of Nek2A to ensure the correct separation of centrosomes.We also found that Cep85 began to aggregate from the cytoplasm to the centrosome in the late G2,the initial stage of centrosome maturation,and how this aggregation is performed and its function during cell division is not yet clear.We determined the role of Cep85 in the division period through knockdown experiments and cellular immunofluorescence experiments,and explored the mechanism of Cep85 aggregation in centrosomes.Cep85 can combine with itself to aggregate and regulate the possible mechanism of Cep85 aggregation.At the same time,we explored the effect of the splice isomer Nek2B on Cep85,and found that both Nek2B and Nek2A can bind to Cep85 and can promote the phosphorylation and aggregation of Cep85.Plk1 can also promote the phosphorylation of Cep85,provided that Cep85 must interact with Nek2.Unlike the mechanism of Plk1,Nek2A does not directly phosphorylate Cep85;therefore we speculate that there is an unknown kinase in the cell that can be activated by Nek2 and directly phosphorylate Cep85.We are isolating and purifying this kinase to further explore the mechanism of Cep85 phosphorylation.In conclusion,the research in this paper has initially revealed the role of Nek2 kinase in centrosome maturation,providing a new perspective for further exploration of the regulatory mechanism of this process.