Conservation in sequence and affinity of human and rodent PDGF ligands and receptors.
Platelet-derived growth factor (PDGF) consists of two chains, PDGF-A and -B, which activate as homo- or heterodimers two receptors, alpha and beta. To test PDGF function in vivo we have generated neutralizing monoclonal antibodies. When analyzed with rat PDGFs only antibodies raised against human PDGF-AA showed cross-species activity. This correlated with complete amino acid sequence conservation of PDGF-A whereas rat PDGF-B differed in six positions when cloned rat PDGF cDNAs were compared with their human homologs within the receptor binding region. Extracellular domains of cloned rat PDGF alpha- and beta-receptor cDNAs did not reflect this difference in cross-species ligand conservation. When rat extracellular domains were expressed as soluble proteins they bound human PDGF-BB with high affinity after immobilization of the purified proteins on solid phase. Dissociation constants were identical to those of their human homologs. Thus, high affinity binding of human PDGF-BB to extracellular domains does not depend on species origin but only on receptor type.
Herren
B
B
Pharma Division, Preclinical Research, F. Hoffmann-La Roche, Basel, Switzerland.
Weyer
K A
KA
Rouge
M
M
Lötscher
P
P
Pech
M
M
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D003429:Cross Reactions; D006801:Humans; D008969:Molecular Sequence Data; D010982:Platelet-Derived Growth Factor / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017479:Receptors, Platelet-Derived Growth Factor / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis
D000911:Antibodies, Monoclonal; D010982:Platelet-Derived Growth Factor; D011994:Recombinant Proteins; D017479:Receptors, Platelet-Derived Growth Factor