TY - JOUR
T1 - Activating and deactivating mutations in the receptor interaction site of GDF5 cause symphalangism or brachydactyly type A2
AU - Seemann, Petra
AU - Schwappacher, Raphaela
AU - Kjær, Klaus Wilbrandt
AU - Krakow, Deborah
AU - Lehmann, Katarina
AU - Dawson, Katherine
AU - Stricker, Sigmar
AU - Pohl, Jens
AU - Plöger, Frank
AU - Staub, Eike
AU - Nickel, Joachim
AU - Sebald, Walter
AU - Knaus, Petra
AU - Mundlos, Stefan
PY - 2005
Y1 - 2005
N2 - Here we describe 2 mutations in growth and differentiation factor 5 (GDF5) that alter receptor-binding affinities. They cause brachydactyly type A2 (L441P) and symphalangism (R438L), conditions previously associated with mutations in the GDF5 receptor bone morphogenetic protein receptor type 1b (BMPR1B) and the BMP antagonist NOGGIN, respectively. We expressed the mutant proteins in limb bud micromass culture and treated ATDC5 and C2C12 cells with recombinant GDF5. Our results indicated that the L441P mutant is almost inactive. The R438L mutant, in contrast, showed increased biological activity when compared with WT GDF5. Biosensor interaction analyses revealed loss of binding to BMPR1A and BMPR1B ectodomains for the L441P mutant, whereas the R438L mutant showed normal binding to BMPR1B but increased binding to BMPR1A, the receptor normally activated by BMP2. The binding to NOGGIN was normal for both mutants. Thus, the brachydactyly type A2 phenotype (L441P) is caused by inhibition of the ligand-receptor interaction, whereas the symphalangism phenotype (R438L) is caused by a loss of receptor-binding specificity, resulting in a gain of function by the acquisition of BMP2-like properties. The presented experiments have identified some of the main determinants of GDF5 receptor-binding specificity in vivo and open new prospects for generating antagonists and superagonists of GDF5.
AB - Here we describe 2 mutations in growth and differentiation factor 5 (GDF5) that alter receptor-binding affinities. They cause brachydactyly type A2 (L441P) and symphalangism (R438L), conditions previously associated with mutations in the GDF5 receptor bone morphogenetic protein receptor type 1b (BMPR1B) and the BMP antagonist NOGGIN, respectively. We expressed the mutant proteins in limb bud micromass culture and treated ATDC5 and C2C12 cells with recombinant GDF5. Our results indicated that the L441P mutant is almost inactive. The R438L mutant, in contrast, showed increased biological activity when compared with WT GDF5. Biosensor interaction analyses revealed loss of binding to BMPR1A and BMPR1B ectodomains for the L441P mutant, whereas the R438L mutant showed normal binding to BMPR1B but increased binding to BMPR1A, the receptor normally activated by BMP2. The binding to NOGGIN was normal for both mutants. Thus, the brachydactyly type A2 phenotype (L441P) is caused by inhibition of the ligand-receptor interaction, whereas the symphalangism phenotype (R438L) is caused by a loss of receptor-binding specificity, resulting in a gain of function by the acquisition of BMP2-like properties. The presented experiments have identified some of the main determinants of GDF5 receptor-binding specificity in vivo and open new prospects for generating antagonists and superagonists of GDF5.
KW - Amino Acid Sequence
KW - Animals
KW - Bone Morphogenetic Protein Receptors, Type I
KW - Bone Morphogenetic Proteins
KW - Carrier Proteins
KW - Cell Differentiation
KW - Cell Line
KW - Embryonic Structures
KW - Fingers
KW - Growth Differentiation Factor 5
KW - Humans
KW - In Situ Hybridization
KW - Limb Deformities, Congenital
KW - Mice
KW - Molecular Sequence Data
KW - Phenotype
KW - Point Mutation
KW - Protein Binding
KW - Protein Conformation
KW - Recombinant Proteins
KW - Sequence Alignment
KW - Tissue Culture Techniques
U2 - 10.1172/JCI25118
DO - 10.1172/JCI25118
M3 - Journal article
C2 - 16127465
SN - 0021-9738
VL - 115
SP - 2373
EP - 2381
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 9
ER -