Functional Studies Of A Centrosome-assoiated Protein Cep88 In The Centrosomal Duplication

Centrosome is the main microtubule organizer of mammalian cells,and is crucial for many biological processes such as formation of the mitotic spindle and establishing the bipolar mitotic spindles.Centrosome dysfunction or abnormal centrosome number is intimately implicated in tumorogenesis,various neurological disorders,certain types of develomental defects,and others.Currently,over 200 new centrosomal proteins have been identified,however,most of their functions in centrosomal regulation are unknown.We have identified Cep88 as an interacting protein of Nek2A,which is an important kinase responsible for the centrosome separation,centrosome structure and spindle formation,chromatin condensation and so on.In order to investigat this novel protein with unkown function,we have established a stable U20S cell line expressing GFP-Cep88,and have determined the centrosomal localization of Cep88.Also the expression level of the protein has been tracked in the cell cycle.On the other hand,we have proved the interaction between Cep88 and Nek2 in many ways.including in vivo and in vitro interaction,immunofluorescence staining,in vitro GST pull down.Even more important is that we have found the kinase activity of Nek2A is arrested by Cep88,measuring by in vitro kinase assay.Based on these data,we will further invesigate the regulatory roles of Cep88 in the structure and function of centrosome as well as in the cell cycle.We believe that our studies would unveil the functions of this novel gene in centrosomal regulation and cell division,and provide something cue for understading centrosomal regulations.