Nuclear localization of the p120 ctn Armadillo-like catenin is counteracted by a nuclear export signal and by E-cadherin expression

• DOI: 10.1073/pnas.96.14.7980
• Publication Date: 2002-07-26T14:38:21Z
• Authors: J. van Hengel; P. Vanhoenacker; K. Staes; F. van Roy
• Keywords: Nuclear export signal

The Armadillo protein p120 ctn associates with the cytoplasmic domain of cadherins and accumulates at cell–cell junctions. Particular proteins such as β-catenin plakophilins show a partly nuclear location, suggesting gene-regulatory activities. For different human E-cadherin-negative carcinoma cancer cell lines we found expression endogenous in nucleus. Expression E-cadherin directed out Previously, reported that gene might encode up to 32 isoforms products alternative splicing. Overexpression B various resulted immunopositivity but never staining. In contrast, upon cDNAs lacking exon B, were detectable within both nuclei cytoplasm. A putative export signal (NES) characteristic leucine-rich motif is encoded by B. This sequence element was shown be required for function autonomously when fused carrier microinjected into nuclei. Moreover, NES endogenously or exogenously expressed sensitive inhibitor leptomycin exogenous down-regulated whereas activation kinase C increased level . These results reveal molecular mechanisms controlling subcellular distribution