Catenin Beta Interacting Protein 1 (CTNNbIP1)

CTNNBIP1 binds CTNNB1 and prevents interaction between CTNNB1 and TCF (T-cell transcription factor) family members. The encoded protein is a negative regulator of the Wnt signaling pathway.

The deduced mouse and human proteins are identical except for 2 amino acid changes. Northern blot analysis of mouse tissues detected a 2.6-kb transcript expressed at high levels in heart, brain, liver, and skeletal muscle, at low levels in kidney, testis, and lung, and at undetectable levels in spleen. Icat was also expressed at fairly constant levels during embryonic mouse development.ICAT contains a 3-helix bundle that binds armadillo repeats 10 to 12 and a C-terminal tail that, like TCF and E-cadherin, binds in the groove formed by armadillo repeats 5 to 9 of CTNNB1.