title: Identification of karyopherin-alpha 2 as an Oct4 associated protein.
abstract: The POU domain transcription factor Oct4 is a master regulator in maintaining self-renewal and pluripotency of embryonic stem (ES) cells. To further explore the functional network of Oct4, the yeast two-hybrid system was used to search for Oct4 interacting proteins. PH domain (containing POU domain and homeodomain) of human OCT4 was used as a bait. From the human testis cDNA library, we identified a strong interaction between OCT4 and karyopherin-alpha 2 (KPNA-2). KPNA2 is involved in active nuclear import of proteins. This finding was confirmed by glutathione S-transferase pull-down and co-immunoprecipitation assays. The interaction between OCT4 and KPNA-2 was further mapped to multiple regions of the two proteins. In addition, we studied nuclear localization signal (NLS) of mouse Oct4 and demonstrated that it is essential for Oct4 nuclear localization. Thus, our data suggest that Oct4 nuclear localization may be mediated by its interaction with KPNA-2.
authors.affiliation: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xiangqun
authors.initials: X
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Ying
authors.initials: Y
authors.lastname: Jin
mesh_terms: D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D009154:Mutation; D050814:Octamer Transcription Factor-3 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D020798:Two-Hybrid System Techniques; D028901:alpha Karyopherins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*
chemical_list: D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D028901:alpha Karyopherins; C087978:karyopherin alpha 2