期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1994
卷号：91
期号：3
页码：989-993
DOI：10.1073/pnas.91.3.989
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Growth factors of the fibroblast growth factor (FGF) family bind receptors whose external domains are organized in a series of immunoglobulin-like loops. We engineered expression constructs in which cDNAs encoding individual immunoglobulin-like domains of the keratinocyte growth factor (KGF/FGF-7) receptor were fused to the mouse immunoglobulin heavy chain Fc domain (HFc). Each chimera was efficiently secreted from NIH 3T3 transfectants and migrated at the predicted molecular mass after SDS/PAGE. Scatchard analysis revealed that the chimera containing immunoglobulin-like domains 2 (D2) and 3 (D3) bound KGF and acidic FGF at high affinities comparable to the native receptor. However, individual immunoglobulin-like domain chimeras demonstrated marked specificity in their ligand interactions. D2-HFc bound acidic FGF at high affinity, whereas it did not detectably interact with KGF. Conversely, D3-HFc bound KGF at high affinity but exhibited no detectable interaction with acidic FGF. Their selective ligand binding properties were confirmed by the specific neutralization of acidic FGF or KGF mitogenic activity using D2 or D3 HFc, respectively. All of these findings establish that the major binding sites for related FGF ligands are localized to distinct receptor immunoglobulin-like domains.
