Study of the effect of a proteasome inhibitor on actin cytoskeleton remodeling in the nerve cells by fluorescence imaging

摘要

The ubiquitin-proteasome system is a major protein degradative pathway involved in the maintenance of cellular structure and function. Actin cytoskeleton plays a critical role in the morphology and structural changes of the nerve cells. Cofilin is a main regulator of actin filament assembly/disassembly. Many diseases of the nerve system are associated with actin-cofilin remodeling. Nevertheless, the role of ubiquitylation in the regulation of cofilin activity and actin cytoskeleton structure in the nerve cells is little investigated. Confocal fluorescence microscopy-based methods are valuable tools for the precise imaging and quantitative evaluation of actin cytoskeleton changes. The aim of this research was to analyze the effect of a proteasome inhibitor MG132 on actin cytoskeleton remodeling in the nerve cells using fluorescence imaging. Cofilin was shown to be colocalized with actin filaments and ubiquitin in hippocampal cells. Analysis of cofilin proteoforms revealed the presence of cofilin modified by K63-linked multiubiquitin chains. The treatment of hippocampal cells with MG132 led to the changes in the structure of actin cytoskeleton, expression of cofilin, and activation of autophagy. Therefore, the results suggest the relationship between cofilin ubiquitylation and actin cytoskeleton remodeling in the nerve cells. It may be important for the development of new methods of diagnosis and treatment of the nerve system disorders.