Biopolymers and cell. 2002; 18 (4): 312 - 318

Subcellular localization of adapter protein Ruk, in HEK293 cells

V. R. Orel, Yu. Ya. Kit, O. Yu. Danyluk, G. Yu. Shuvajeva, N. I. Ihumenceva, I. T. Gout, L. B. Drobot

Subcellular localization of adapter protein Rukt has been investi¬gated in human embryonic kidney HEK293 cells transfected with pRc/CMV2lRukl-Glu-tag. Using immunofluorescence microscopy, it was shown that the recombinant protein was distributed diffusely in both cytoplasm and nucleus, but with punctated structures in the nucleus, which correspond in all probability to the nucleolus. The Rukt localization in the nucleus was confirmed by Western blotting of nucleic extracts prepared from transfected HEK293 cells using monoclonal anti-Glu-tag antibodies, as well as from nontransfected HEK293 and U937 cells using polyclonal anti-Ruk antibodies. The ability of affine purified Rukt Glu-tagged preparation to bind to DNA from calf thymus, but not to Escherichia coli DNA, was revealed by the immunodot-blot analysis. The nuclear localization of Rukt suggests that this adapter protein is involved in some new, yet unrecognized functions, in the eukaryotic cell nucleus.