Editors' ChoiceDevelopment

Stability is Only Part of the Process

Science's STKE  11 Jul 2000:
Vol. 2000, Issue 40, pp. tw9
DOI: 10.1126/stke.2000.40.tw9

Signaling by the Wnt pathway involves stabilization of β-catenin. Guger and Gumbiner created mutants of β-catenin in which the phosphorylation sites in the NH2-terminal domain were mutated to alanine or were mutated to aspartic acid to mimic constitutive phosphorylation. These constructs were tested for the ability to form an ectopic axis in Xenopus embryos and for the ability to induce the expression of siamois in an in vitro assay in which protein levels were constant. The Asp mutant exhibited a higher specific activity than wild-type β-catenin in both assays. The authors propose that the NH2-terminal phosphorylation sites of β-catenin can regulate its signaling activity independently of the effect on β-catenin stability.

Guger, K.A., and Gumbiner, B.M. (2000) A mode of regulation of β-catenin signaling activity in Xenopus embryos independent of its levels. Dev. Biol. 223: 441-448. [Online Journal]