Structure of the Dual-Mode Wnt Regulator Kremen1 and Insight into Ternary Complex Formation with LRP6 and Dickkopf

Matthias Zebisch; Verity A Jackson; Yuguang Zhao; E Yvonne Jones

doi:10.1016/j.str.2016.06.020

Structure of the Dual-Mode Wnt Regulator Kremen1 and Insight into Ternary Complex Formation with LRP6 and Dickkopf

Structure. 2016 Sep 6;24(9):1599-605. doi: 10.1016/j.str.2016.06.020. Epub 2016 Aug 11.

Authors

Matthias Zebisch¹, Verity A Jackson², Yuguang Zhao², E Yvonne Jones³

Affiliations

¹ Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK. Electronic address: matthias.zebisch@evotec.com.
² Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
³ Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK. Electronic address: yvonne@strubi.ox.ac.uk.

Abstract

Kremen 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 Å. 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 β-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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Motifs
Binding Sites
Cloning, Molecular
Crystallography, X-Ray
Gene Expression
HEK293 Cells
Humans
Intercellular Signaling Peptides and Proteins / chemistry*
Intercellular Signaling Peptides and Proteins / genetics
Intercellular Signaling Peptides and Proteins / metabolism
Low Density Lipoprotein Receptor-Related Protein-6 / chemistry*
Low Density Lipoprotein Receptor-Related Protein-6 / genetics
Low Density Lipoprotein Receptor-Related Protein-6 / metabolism
Membrane Proteins / chemistry*
Membrane Proteins / genetics
Membrane Proteins / metabolism
Models, Molecular
Protein Binding
Protein Conformation, alpha-Helical
Protein Conformation, beta-Strand
Protein Interaction Domains and Motifs
Protein Multimerization
Recombinant Proteins / chemistry
Recombinant Proteins / genetics
Recombinant Proteins / metabolism

Substances

DKK1 protein, human
Intercellular Signaling Peptides and Proteins
KREMEN1 protein, human
LRP6 protein, human
Low Density Lipoprotein Receptor-Related Protein-6
Membrane Proteins
Recombinant Proteins

Abstract

Publication types

MeSH terms

Substances

Grants and funding