Changes

* Beta-catenin phosphorylation at serine 45 (Ser45), threonine 41 (Thr41), Ser37, and Ser33 is critical for beta-catenin degradation.[http://jb.oxfordjournals.org/cgi/content/abstract/132/5/697 source]* Regulation of beta-catenin phosphorylation is a central part of the canonical Wnt signaling pathway.[http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ProduktNr=223838&ArtikelNr=66755&filename=66755.pdf source]* Ser-X-X-X-Ser (X is any amino acid) motif is obligatory for beta-catenin phosphorylation by GSK3.[http://lib.bioinfo.pl/auth:He,X source]* Beta-catenin phosphorylation/degradation and its regulation by Wnt can occur normally in the absence of Thr41 as long as the Ser-X-X-X-Ser motif/spacing is preserved.[http://pubs.acs.org/cgi-bin/abstract.cgi/bichaw/2006/45/i16/abs/bi0601149.html source]* GSK3’s substrate specificity is unique in that phosphorylation of substrate only occurs if a phosphoserine or phosphotyrosine is present four residues C-terminal to the site of GSK phosphorylation.[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11430833&dopt=Abstract source]* A phosphorylation cascade starts from GSK3 itself and initiates it in beta-catenin.[http://www.genesdev.org/cgi/content/full/16/16/2073 source]