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Regulation of β-catenin trafficking to the membrane in living cells
- Source :
-
Cellular Signalling . Feb2009, Vol. 21 Issue 2, p339-348. 10p. - Publication Year :
- 2009
-
Abstract
- Abstract: β-catenin is a key mediator of the Wnt signaling process and accumulates in the nucleus and at the membrane in response to Wnt-mediated inhibition of GSK-3β. In this study we used live cell photobleaching experiments to determine the dynamics and rate of recruitment of β-catenin at membrane adherens junctions (cell adhesion) and membrane ruffles (cell migration). First, we confirmed the nuclear-cytoplasmic shuttling of GFP-tagged β-catenin, and found that a small mobile pool of β-catenin can move from the nucleus to membrane ruffles in NIH 3T3 fibroblasts with a t 0.5 of ~30 s. Thus, β-catenin can shuttle between the nucleus and plasma membrane. The localized recruitment of β-catenin-GFP to membrane ruffles was more rapid, and the strong recovery observed after bleaching (mobile fraction 53%, t 0. 5 ~5 s) is indicative of high turnover and transient association. In contrast, β-catenin-GFP displayed poor recovery at adherens junctions in MDCK epithelial cells (mobile fraction 10%, t 0. 5 ~8 s), indicating stable retention at these membrane structures. We previously identified IQGAP1 as an upstream regulator of β-catenin at the membrane, and this is supported by photobleaching assays which now reveal IQGAP1 to be more stably anchored at membrane ruffles than β-catenin. Further analysis showed that LiCl-mediated inactivation of the kinase GSK-3β increased β-catenin membrane ruffle staining; this correlated with a faster rate of recruitment and not increased membrane retention of β-catenin. In summary, β-catenin displays a high turnover rate at membrane ruffles consistent with its dynamic internalization and recycling at these sites by macropinocytosis. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 08986568
- Volume :
- 21
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Cellular Signalling
- Publication Type :
- Academic Journal
- Accession number :
- 35927262
- Full Text :
- https://doi.org/10.1016/j.cellsig.2008.11.004