The association of 14-3-3_γ and GFAP determined by phosphorylation of GFAP serine 18 regulates intermediate filaments dynamics in astrocyte

【作者】 李慧惠； 郭焱； 于常海； 丁明孝； 王晶晶； 陈建国；

【机构】 北京大学生命科学学院；

【摘要】 <正>Glial fibrillary acidic protein (GFAP) is the major intermediate filament(IF) protein of astrocytes. 14-3-3 family members, found in all eukaryotes, play critical roles in many signal transduction pathways. We showed that 14-3-3y proteins associate with both soluble and filamentous GFAP independent on vimentin, the other kind of intermediate filament proteins in primary cultured astrocytes. Phosphatase inhibitor Calyculin A treatment and coimmunoprecipitation results supported that 14-3-3y proteins bind to phosphorylated GFAP. Domain deletion mutants study and FRET assay showed that this interaction is determined by the head domain of GFAP. Phophorylation site specific mutations further indicated that GFAP serine 18 is essential for the associtation of GFAP with 14-3-3y. Using cell synchronization we found that 14-3-3y associated with GFAP during S/G2/M phases of the cell cycle. Furthermore, overexpression of 14-3-3y destroyed GFAP assembly and affected the movement of glial filaments detected by FRAP assay. Our experiments first illustrate the relationship between 14-3-3 proteins and the IFs dynamics in nervous system. We demonstrate that the binding of 14-3-3y to GFAP may play potential roles in regulating dynamics of GFAP network, or sequester other 14-3-3y-associated proteins, and in更多还原