FHL2通过相互作用抑制Id2的功能活性  

FHL2 Inhibits Functional Activity of Id2 by Their Interaction

作　　者：韩为东[1] 赵亚力[1] 伍志强[1] 司艺玲[1] 杨洁[1] 田丽媛[1] 孟元光[2] 

机构地区：[1]解放军总医院基础医学研究所分子生物学实验室 [2]解放军总医院妇产科,北京100853

出　　处：《中国生物化学与分子生物学报》2008年第9期810-817,共8页Chinese Journal of Biochemistry and Molecular Biology

基　　金：国家自然科学基金(No.30670809)资助~~

摘　　要：分化抑制蛋白2(Id2)通过抑制碱性螺旋-环-螺旋(bHLH)类转录因子的功能活性调控多种组织细胞的分化发育,并参与人类多种肿瘤的发生与进展.Id2相互作用蛋白可能调控其翻译后的功能活性.本研究以HLH结构域缺失的Id2作为诱饵蛋白,采用酵母双杂交方法对MCF-7 cDNA文库进行筛选,识别了1个新的Id2相互作用蛋白FHL2(属于LIM蛋白家族的一员),哺乳动物双杂交实验系统验证了Id2与FHL2之间的相互作用,同时证实,该作用不依赖于Id2中的HLH结构域;GST-pulldown、免疫共沉淀方法,进一步证实FHL2/Id2之间的相互作用;免疫荧光共定位实验结果证实,FHL2/Id2相互作用主要发生在细胞核内;共转染实验结果发现,FHL2通过相互作用阻抑了Id2对bHLH类转录因子E47的功能抑制活性.总之,本研究识别了1个新的Id2相互作用蛋白FHL2,通过直接的相互作用,FHL2抑制了Id2的功能活性,FHL2可能参与调控Id2介导的细胞分化与发育过程,并可能参与肿瘤的发生与进展.Id2（inhibitor of differentiation 2） protein is a key modulator of cellular differentiation and multiple tissue development as a natural inhibitor of bHLH（basic helix-loop-helix） transcriptional factors.Deregulation of Id2 function involves tumorigenesis and tumor progression.The functional activity of Id2 protein may be regulated by its interacting factors at the post-translational level.Here,a yeast two-hybrid screen was performed via an HLH domain-deleted Id2 as bait and a MCF-7 cDNA library to identify proteins involved in regulating Id2 functional activity.This screen identified the LIM protein FHL2 as a novel Id2 interacting protein,and the FHL2/Id2 association was confirmed by mammalian two-hybrid experimental system,meanwhile,this interaction was confirmed to be independent on the HLH domain contained in Id2.Results from coimmunoprecipitation（CoIP） assays further revealed that FHL2 interacts with Id2 in vitro and in vivo.The FHL2/Id2 association was demonstrated to preferentially occur in the nucleus by immunofluorescence assays.Importantly,our in vivo data based on cotransfection experiments revealed that FHL2 is able to restore E47,a ubiquitously expressed bHLH factor,mediated transcription by repressing Id2 Taken together,we identified a novel Id2 interacting protein FHL2.FHL2 inhibits the functional activity of Id2 through direct interaction,by which FHL2 may regulate Id2-mediated cellular differentiation and development,and even tumorigenesis and progression.

关 键 词：FHL2 分化抑制蛋白2(Id2) 相互作用 抑制子 

分 类 号：Q78[生物学—分子生物学] Q25