Homologue scanning mutagenesis of heregulin reveals receptor specific binding epitopes.
The EGF domain of heregulin has all the receptor binding characteristics of full-length heregulin and has strong homology to the ligands for erbB-1. Despite this, it does not bind erbB-1 but instead binds erbB-3 and erbB-4. The sequence similarity between HRG and the erbB-1 ligands suggest that a few residues are responsible for receptor binding specificity. To determine the sequences involved in receptor binding, we performed homologue scanning mutagenesis on the EGF domain of HRGalpha using sequences of TGFalpha or EGF. We found three sets of mutations in the N-terminal subdomain that were responsible for receptor binding specificity. Mutations in the C-terminal subdomain affected the binding affinity, but did appear to confer any specificity.
Harris
A
A
Department of Biodiscovery Research, Berlex Biosciences, Richmond, California, 94804, USA.
Adler
M
M
Brink
J
J
Lin
R
R
Foehr
M
M
Ferrer
M
M
Langton-Webster
B C
BC
Harkins
R N
RN
Thompson
S A
SA
D000230:Adenocarcinoma; D000595:Amino Acid Sequence; D001667:Binding, Competitive; D001943:Breast Neoplasms; D018604:Epitope Mapping; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008024:Ligands; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009414:Nerve Growth Factors / Q000737:chemistry* / Q000235:genetics; D020880:Neuregulins; D018719:Erb-b2 Receptor Tyrosine Kinases; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D016211:Transforming Growth Factor alpha / Q000235:genetics; D014407:Tumor Cells, Cultured
D006023:Glycoproteins; D008024:Ligands; D009414:Nerve Growth Factors; D020880:Neuregulins; D018719:Erb-b2 Receptor Tyrosine Kinases; D017475:Receptors, Nerve Growth Factor; D016211:Transforming Growth Factor alpha