title: Structure of Gremlin-1 and analysis of its interaction with BMP-2.
abstract: Bone morphogenetic protein 2 (BMP-2) is a member of the transforming growth factor-β (TGF-β) signalling family and has a very broad biological role in development. Its signalling is regulated by many effectors: transmembrane proteins, membrane-attached proteins and soluble secreted antagonists such as Gremlin-1. Very little is known about the molecular mechanism by which Gremlin-1 and other DAN (differential screening-selected gene aberrative in neuroblastoma) family proteins inhibit BMP signalling. We analysed the interaction of Gremlin-1 with BMP-2 using a range of biophysical techniques, and used mutagenesis to map the binding site on BMP-2. We have also determined the crystal structure of Gremlin-1, revealing a similar conserved dimeric structure to that seen in other DAN family inhibitors. Measurements using biolayer interferometry (BLI) indicate that Gremlin-1 and BMP-2 can form larger complexes, beyond the expected 1:1 stoichiometry of dimers, forming oligomers that assemble in alternating fashion. These results suggest that inhibition of BMP-2 by Gremlin-1 occurs by a mechanism that is distinct from other known inhibitors such as Noggin and Chordin and we propose a novel model of BMP-2-Gremlin-1 interaction yet not seen among any BMP antagonists, and cannot rule out that several different oligomeric states could be found, depending on the concentration of the two proteins.
authors.affiliation: Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K.
authors.forename: Miglė
authors.initials: M
authors.lastname: Kišonaitė
authors.affiliation: Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K.
authors.forename: Xuelu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K. mh256@cam.ac.uk.
authors.forename: Marko
authors.initials: M
authors.lastname: Hyvönen
mesh_terms: D055396:Bone Morphogenetic Protein 2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D018360:Crystallography, X-Ray; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D000099176:Noggin Protein
chemical_list: D055396:Bone Morphogenetic Protein 2; D002352:Carrier Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D000099176:Noggin Protein; C525718:BMP2 protein, human; C486399:GREM1 protein, human; C054234:chordin
keywords: Gremlin; X-ray crystallography; bone morphogenetic protein (BMP); differential screening-aberrative in neuroblastoma (DAN); extracellular antagonism; structural biology; transforming growth factor-β (TGF-β)