Biopolym. Cell. 2013; 29(2):131-135.
Genomics, Transcriptomics and Proteomics
Interaction of ubiquitin ligase CBL with LMP2A protein of Epstein-Barr virus occurs via PTB domain of CBL and does not depend on adaptor ITSN1
1Dergai O. V., 1Dergai M. V., 1Gudkova D. O., 1Tsyba L. O., 1Skrypkina I. Ya., 1Rynditch A. V.
  1. State Key Laboratory of Molecular and Cellular Biology
    Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680


Aim. Previously Latent membrane protein 2A (LMP2A) of Epstein-Barr virus was found to be ubiquitylated by CBL ubiquitin ligase but no direct interaction of LMP2A with CBL was reported. We aimed to explore this interaction and study a possibility of adaptor protein involvement. Taking into consideration that both LMP2A and CBL were shown to interact with endocytic adaptor protein intersectin 1 (ITSN1), we assumed that the latter could serve as a scaffold for LMP2A/CBL complex. Methods. We used an immunofluorescence and coimmuno- precipitation approaches to test a mutual complex formation of ITSN1, CBL and LMP2A proteins. Results. LMP2A coimmunoprecipitated with CBL while LMP2A did not interact with CBL G306E mutant harboring inactive phosphotyrosine-binding domain. We observed a triple colocalization of ITSN1, CBL and LMP2A signals in MCF-7 cells as well as coprecipitation of all mentioned proteins. Overexpression of ITSN1 did not affect the efficiency of complex formation of LMP2A with CBL. Moreover, LMP2A mutant unable to interact with ITSN1 was readily precipitated with CBL. Conclusions. LMP2A can be engaged in the complex together with endocytic adaptor ITSN1 and ubiquitin ligase CBL. We show that PTB domain of CBL is responsible for interaction with LMP2A. ITSN1 is not required for LMP2A recruiting to CBL.
Keywords: intersectin 1, CBL, LMP2A, Epstein-Barr virus


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