Premium
The structure of GFRα1 domain 3 reveals new insights into GDNF binding and RET activation
Author(s) -
Leppänen VeliMatti,
Bespalov Maxim M,
RunebergRoos Pia,
Puurand Ülo,
Merits Andres,
Saarma Mart,
Goldman Adrian
Publication year - 2004
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600174
Subject(s) - library science , computer science
Glial cell line‐derived neurotrophic factor (GDNF) binds to the GDNF family co‐receptor α1 (GFRα1) and activates RET receptor tyrosine kinase. GFRα1 has a putative domain structure of three homologous cysteine‐rich domains, where domains 2 and 3 make up a central domain responsible for GDNF binding. We report here the 1.8 Å crystal structure of GFRα1 domain 3 showing a new protein fold. It is an all‐α five‐helix bundle with five disulfide bridges. The structure was used to model the homologous domain 2, the other half of the GDNF‐binding fragment, and to construct the first structural model of the GDNF–GFRα1 interaction. Using site‐directed mutagenesis, we identified closely spaced residues, Phe213, Arg224, Arg225 and Ile229, comprising a putative GDNF‐binding surface. Mutating each one of them had slightly different effects on GDNF binding and RET phosphorylation. In addition, the R217E mutant bound GDNF equally well in the presence and absence of RET. Arg217 may thus be involved in the allosteric properties of GFRα1 or in binding RET.