Peptides identify the critical hotspots involved in the biological activation of the insulin receptor.
We used phage display to generate surrogate peptides that define the hotspots involved in protein-protein interaction between insulin and the insulin receptor. All of the peptides competed for insulin binding and had affinity constants in the high nanomolar to low micromolar range. Based on competition studies, peptides were grouped into non-overlapping Sites 1, 2, or 3. Some Site 1 peptides were able to activate the tyrosine kinase activity of the insulin receptor and act as agonists in the insulin-dependent fat cell assay, suggesting that Site 1 marks the hotspot involved in insulin-induced activation of the insulin receptor. On the other hand, Site 2 and 3 peptides were found to act as antagonists in the phosphorylation and fat cell assays. These data show that a peptide display can be used to define the molecular architecture of a receptor and to identify the critical regions required for biological activity in a site-directed manner.
Pillutla
Renuka C
RC
Department of Molecular Biology, DGI BioTechnologies, Edison, New Jersey 08818, USA.
Hsiao
Ku-chuan
KC
Beasley
James R
JR
Brandt
Jakob
J
Østergaard
Søren
S
Hansen
Per Hertz
PH
Spetzler
Jane C
JC
Danielsen
Gillian M
GM
Andersen
Asser S
AS
Brissette
Renee E
RE
Lennick
Michael
M
Fletcher
Paul W
PW
Blume
Arthur J
AJ
Schäffer
Lauge
L
Goldstein
Neil I
NI
D017667:Adipocytes / Q000378:metabolism; D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007700:Kinetics; D051379:Mice; D016297:Mutagenesis, Site-Directed; D010452:Peptide Biosynthesis; D019151:Peptide Library; D010455:Peptides; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011972:Receptor, Insulin / Q000737:chemistry / Q000378:metabolism*
D019151:Peptide Library; D010455:Peptides; D004247:DNA; D011972:Receptor, Insulin