Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Sci. STKE, 5 September 2000
Vol. 2000, Issue 48, p. tw2
[DOI: 10.1126/stke.2000.48.tw2]


Cancer APC's NES Helps Shuttle β-Catenin PDQ

Adenomatous polyposis coli (APC) promotes the degradation of β-catenin. When APC is mutated, as in colon cancer cells, β-catenin accumulates in the nucleus, where it functions as a transcriptional coactivator of T-cell factor. The mechanism by which APC regulates β-catenin degradation has remained elusive. Now, Rosin-Arbesfeld et al. demonstrate that APC contains a functional nuclear export signal (NES), and that APC shuttles β-catenin into the cytoplasm for subsequent proteasomal degradation. COOH-terminal fragments of APC remained exclusively cytoplasmic. Treatment of APC-expressing cells with leptomycin B, a nuclear export inhibitor, revealed that APC remains in the nucleus, suggesting that an NES exists in the COOH-terminus of APC. The authors observed that β-catenin colocalized with wild-type APC in the cytoplasm, or in the nucleus with NES-mutated APC. Gene reporter assays also indicated that wild-type APC reduced the ability of β-catenin to cotransactivate luciferase expression, whereas NES-mutated APC was unable to repress β-catenin-mediated transcription.

Rosin-Arbesfeld, R., Townsley, F., and Bienz, M. (2000) The APC tumour suppressor has a nuclear export function. Nature 406: 1009-1012. [Online Journal]

Citation: APC's NES Helps Shuttle β-Catenin PDQ. Sci. STKE 2000, tw2 (2000).

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882