5fww
From Proteopedia
Wnt modulator Kremen in complex with DKK1 (CRD2) and LRP6 (PE3PE4)
Structural highlights
Disease[LRP6_HUMAN] Coronary artery disease - hyperlipidemia - hypertension - diabetes - osteoporosis. The disease is caused by mutations affecting the gene represented in this entry. [DKK1_HUMAN] Idiopathic juvenile osteoporosis. Function[LRP6_HUMAN] Component of the Wnt-Fzd-LRP5-LRP6 complex that triggers beta-catenin signaling through inducing aggregation of receptor-ligand complexes into ribosome-sized signalsomes. Cell-surface coreceptor of Wnt/beta-catenin signaling, which plays a pivotal role in bone formation. The Wnt-induced Fzd/LRP6 coreceptor complex recruits DVL1 polymers to the plasma membrane which, in turn, recruits the AXIN1/GSK3B-complex to the cell surface promoting the formation of signalsomes and inhibiting AXIN1/GSK3-mediated phosphorylation and destruction of beta-catenin. Required for posterior patterning of the epiblast during gastrulation (By similarity).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [DKK1_HUMAN] Antagonizes canonical Wnt signaling by inhibiting LRP5/6 interaction with Wnt and by forming a ternary complex with the transmembrane protein KREMEN that promotes internalization of LRP5/6. DKKs play an important role in vertebrate development, where they locally inhibit Wnt regulated processes such as antero-posterior axial patterning, limb development, somitogenesis and eye formation. In the adult, Dkks are implicated in bone formation and bone disease, cancer and Alzheimer disease.[11] [KREM1_HUMAN] Receptor for Dickkopf protein. Cooperates with Dickkopf to block Wnt/beta-catenin signaling (By similarity). Publication Abstract from PubMedKremen 1 and 2 have been identified as co-receptors for Dickkopf (Dkk) proteins, hallmark secreted antagonists of canonical Wnt signaling. We present here three crystal structures of the ectodomain of human Kremen1 (KRM1ECD) at resolutions between 1.9 and 3.2 A. KRM1ECD emerges as a rigid molecule with tight interactions stabilizing a triangular arrangement of its Kringle, WSC, and CUB structural domains. The structures reveal an unpredicted homology of the WSC domain to hepatocyte growth factor. We further report the general architecture of the ternary complex formed by the Wnt co-receptor Lrp5/6, Dkk, and Krm, determined from a low-resolution complex crystal structure between beta-propeller/EGF repeats (PE) 3 and 4 of the Wnt co-receptor LRP6 (LRP6PE3PE4), the cysteine-rich domain 2 (CRD2) of DKK1, and KRM1ECD. DKK1CRD2 is sandwiched between LRP6PE3 and KRM1Kringle-WSC. Modeling studies supported by surface plasmon resonance suggest a direct interaction site between Krm1CUB and Lrp6PE2. Structure of the Dual-Mode Wnt Regulator Kremen1 and Insight into Ternary Complex Formation with LRP6 and Dickkopf.,Zebisch M, Jackson VA, Zhao Y, Jones EY Structure. 2016 Sep 6;24(9):1599-1605. doi: 10.1016/j.str.2016.06.020. Epub 2016 , Aug 11. PMID:27524201[12] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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