GFR-ALPHA-4, A NEW GDNF FAMILY RECEPTOR

GFR alpha-1, GFR alpha-2, and GFR alpha-3 constitute a family of struc turally related, glycosyl-phosphatidylinosital-linked, cell surface pr oteins, two of which, GFR alpha-1 and GFR alpha-2, are components of t he receptor complex for the neurotrophic factors GDNF and neurturin, r espectively. By screening an embryonic chicken brain cDNA library with a GFR alpha-1 probe at low stringency, we isolated cDNAs encoding an additional member of the GFR alpha family, GFR alpha-4. The nucleotide sequence predicts a 431-amino-acid secreted protein that is more clos ely related to GFR alpha-1 and GFR alpha-2 than to GFR alpha-3. GFR al pha-4 mRNA is expressed in distinctive patterns in the brain and sever al other organs and tissues of the chicken embryo. Our findings extend the family of GFR alpha proteins and provide information about the ti ssues in which GFR alpha-4 may function during development.