Inhibition of binding of phospholipase C gamma 1 SH2 domains to phosphorylated epidermal growth factor receptor by phosphorylated peptides.
A series of tyrosine-containing peptides 1-12: [formula: see text] (six pairs with and without the tyrosine phosphorylated) has been synthesized. The peptides were derived from tyrosine autophosphorylation sites in the epidermal growth factor receptor (EGFR): Tyr 992, 1068, 1148 and 1173. Peptide 1, derived from the Tyr 992 site, inhibited binding of a 35S-labelled fusion protein containing both of the SH2 domains from PLC gamma 1 to the phosphorylated EGFR with an IC50 of 8 microM. All of the phosphorylated peptides except 11 (1, 3, 5, 7 and 9) inhibited this binding to some degree (20-55%) at 10 microM. The nonphosphorylated peptides were inactive in this assay. The nonphosphorylated peptides 2, 4, 6, 8, 10 and 12 were obtained by standard solid-phase synthetic methodologies using both Boc/benzyl and Fmoc/tert-butyl strategies. The phosphorylated peptides 1, 3, 5, 7, 9 and 11 were similarly obtained using a Fmoc/tert-butyl strategy incorporating unprotected N alpha-Fmoc-Tyr, followed by phosphitylation and oxidation of the tyrosine in the resin-bound peptide. In addition, Asp-Ala-Asp-Glu-Phe992(4-CH2PO3H2)-Leu-Ile-Pro-Gln-Gln-Gly-O H (15), an analog of 1 incorporating an enzymatically stable phosphotyrosine mimic, 4-phosphonomethyl-L-phenylalanine, was synthesized and found to be inactive.
McNamara
D J
DJ
Department of Medicinal Chemistry, Warner-Lambert Company, Ann Arbor, Michigan.
Dobrusin
E M
EM
Zhu
G
G
Decker
S J
SJ
Saltiel
A R
AR
D000595:Amino Acid Sequence; D001665:Binding Sites; D066246:ErbB Receptors / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000494:pharmacology*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding / Q000187:drug effects; D015398:Signal Transduction / Q000502:physiology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
D010455:Peptides; C083973:4-phosphonomethylphenylalanine; D014443:Tyrosine; D010649:Phenylalanine; D066246:ErbB Receptors; D010738:Type C Phospholipases