The Phospho-EGF Receptor Pathway Sampler Kit provides an economical means to evaluate the activation status of multiple members of the EGF receptor pathway, including phosphorylated EGF receptor, Stat5, c-Cbl, Shc, Gab1, PLCγ1, Akt and p44/42 MAPK. The kit includes enough primary and secondary antibodies to perform two western blot experiments.
Specificity / Sensitivity
Each antibody in the Phospho-EGF Receptor Pathway Sampler Kit recognizes the phosphorylated form of its specific target. Phospho-EGF Receptor (Tyr1068) (D7A5) XP® Rabbit mAb may cross-react weakly with other tyrosine-phosphorylated proteins. Phospho-Gab1 (Tyr627) (C32H2) Rabbit mAb may cross-react with phosphorylated Gab2, Gab3, or activated receptor tyrosine kinases. Phospho-Shc (Tyr239/240) Antibody may cross-react with activated EGF receptor protein.
Source / Purification
Activation state polyclonal antibodies are produced by immunizing animals with synthetic phosphopeptides corresponding to residues surrounding Tyr239/240 of human Shc. Polyclonal antibodies are purified by protein A and peptide affinity chromatography. Rabbit monoclonal antibodies are produced by immunizing animals with synthetic phosphopeptides corresponding to residues surrounding Tyr700 of c-Cbl, Tyr1068 of human EGF receptor, Tyr694 of Stat5a, Tyr627 of human Gab1, Ser473 of human Akt, Thr202/Tyr204 of human p44 MAP kinase, or Tyr783 of human PLCγ1 protein.
The epidermal growth factor (EGF) receptor is a transmembrane tyrosine kinase that belongs to the HER/ErbB protein family. Ligand binding results in receptor dimerization, autophosphorylation, activation of downstream signaling, internalization, and lysosomal degradation (1,2). Phosphorylation of EGF receptor (EGFR) at Tyr845 in the kinase domain is implicated in stabilizing the activation loop, maintaining the active state enzyme, and providing a binding surface for substrate proteins (3,4). c-Src is involved in phosphorylation of EGFR at Tyr845 (5). The SH2 domain of PLCγ binds at phospho-Tyr992, resulting in activation of PLCγ-mediated downstream signaling (6). Phosphorylation of EGFR at Tyr1045 creates a major docking site for the adaptor protein c-Cbl, leading to receptor ubiquitination and degradation following EGFR activation (7,8). The GRB2 adaptor protein binds activated EGFR at phospho-Tyr1068 (9). A pair of phosphorylated EGFR residues (Tyr1148 and Tyr1173) provide a docking site for the Shc scaffold protein, with both sites involved in MAP kinase signaling activation (2). Phosphorylation of EGFR at specific serine and threonine residues attenuates EGFR kinase activity. EGFR carboxy-terminal residues Ser1046 and Ser1047 are phosphorylated by CaM kinase II; mutation of either of these serines results in upregulated EGFR tyrosine autophosphorylation (10).