concanavalin-a and phenylalanylglycine

beta-Catenin nuclear import has been found to be independent of classical nuclear localization signal (NLS) nuclear import factors. Here, we test the hypothesis that beta-catenin interacts directly with nuclear pore proteins to mediate its own transport. We show that beta-catenin, unlike importin-beta, does not interact detectably with Phe/Gly(FG)-repeat-rich nuclear pore proteins or nucleoporins (Nups). Moreover, unlike NLS-containing proteins, beta-catenin nuclear import is not inhibited by wheat germ agglutinin (WGA) or excess importin-beta. These results suggest beta-catenin nuclear translocation does not involve direct interactions with FG-Nups. However, beta-catenin has two regions that can target it to the nucleus, and its import is cold sensitive, indicating that beta-catenin nuclear import is still an active process. Transport is blocked by a soluble form of the C-cadherin cytoplasmic domain, suggesting that masking of the nuclear targeting signal may be a mechanism of regulating beta-catenin subcellular localization.

Topics: Active Transport, Cell Nucleus; Animals; beta Catenin; beta Karyopherins; beta-Galactosidase; Biological Transport; Cell Nucleus; Chlorocebus aethiops; Concanavalin A; COS Cells; Cytoskeletal Proteins; Cytosol; Dipeptides; Nuclear Localization Signals; Nuclear Pore; Nuclear Pore Complex Proteins; Nuclear Proteins; Protein Structure, Tertiary; Recombinant Proteins; Temperature; Trans-Activators; Wheat Germ Agglutinins; Xenopus laevis; Xenopus Proteins