4nm7
From Proteopedia
Crystal structure of GSK-3/Axin complex bound to phosphorylated Wnt receptor LRP6 e-motif
Structural highlights
Disease[AXIN1_HUMAN] Defects in AXIN1 are involved in hepatocellular carcinoma (HCC) [MIM:114550].[1] [2] Defects in AXIN1 are a cause of caudal duplication anomaly (CADUA) [MIM:607864]. Caudal duplication anomaly is characterized by the occurrence of duplications of different organs in the caudal region. Note=Caudal duplication anomaly is associated with hypermethylation of the AXIN1 promoter.[3] Function[AXIN1_HUMAN] Component of the beta-catenin destruction complex required for regulating CTNNB1 levels through phosphorylation and ubiquitination, and modulating Wnt-signaling. Controls dorsoventral patterning via two opposing effects; down-regulates CTNNB1 to inhibit the Wnt signaling pathway and ventralize embryos, but also dorsalizes embryos by activating a Wnt-independent JNK signaling pathway. In Wnt signaling, probably facilitates the phosphorylation of CTNNB1 and APC by GSK3B. Likely to function as a tumor suppressor. Facilitates the phosphorylation of TP53 by HIPK2 upon ultraviolet irradiation. Enhances TGF-beta signaling by recruiting the RNF111 E3 ubiquitin ligase and promoting the degradation of inhibitory SMAD7. Also component of the AXIN1-HIPK2-TP53 complex which controls cell growth, apoptosis and development.[4] [5] [6] Publication Abstract from PubMedGlycogen synthase kinase-3 (GSK-3) is a key regulator of many cellular signaling pathways. Unlike most kinases, GSK-3 is controlled by inhibition rather than by specific activation. In the insulin and several other signaling pathways, phosphorylation of a serine present in a conserved sequence near the amino terminus of GSK-3 generates an auto-inhibitory peptide. In contrast, Wnt/beta-catenin signal transduction requires phosphorylation of Ser/Pro rich sequences present in the Wnt co-receptors LRP5/6, and these motifs inhibit GSK-3 activity. We present crystal structures of GSK-3 bound to its phosphorylated N-terminus and to two of the phosphorylated LRP6 motifs. A conserved loop unique to GSK-3 undergoes a dramatic conformational change that clamps the bound pseudo-substrate peptides, and reveals the mechanism of primed substrate recognition. The structures rationalize target sequence preferences and suggest avenues for the design of inhibitors selective for a subset of pathways regulated by GSK-3. DOI: http://dx.doi.org/10.7554/eLife.01998.001. Structural basis of GSK-3 inhibition by N-terminal phosphorylation and by the Wnt receptor LRP6.,Stamos JL, Chu ML, Enos MD, Shah N, Weis WI Elife. 2014 Mar 18;3:e01998. doi: 10.7554/eLife.01998. PMID:24642411[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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