Cystin has a functional nuclear localization signal at the N-terminus.

<p>The subcellular localization of cystin and its variants was determined by immunoblotting. The wild-type cystin_wt, the N-terminal deletion mutant cystin_▵1-20, and the site-directed mutant cystin_G2A, each tagged with GFP were stably-transfected in mIMCD-3 cells. (<b>A</b>) The distribution of wild-type cystin_wt::GFP in the four fractions prepared from mIMCD-3 cells is shown by western blot (above) and using densitometry (below). (<b>B</b>) The distribution for cystin_▵1-20::GFP is similarly shown by western and densitometry. (<b>C</b>) The distribution of the site-directed mutant cystin_G2A::GFP is shown in the four fractions of mIMCD-3 cells using western blot analysis and densitometry. (<b>D</b>) To demonstrate the reliability of the fractionation protocol, wild type mIMCD-3 cells were fractionated (n = 5 experiments) and 10 µg of each fraction was analyzed by western blotting with fraction specific marker as indicated. The fractions are cytosol (1), membrane (2), nuclear (3) and cytoskeleton (4).