Human recombinant double-chain HGF was a gift from Genentech (San Francisco, CA). The monoclonal antibodies PTP1B, SHP-1, SHP-2, LAR, and KAP and the secondary antibodies against mouse and rabbit conjugated horseradish peroxidase (HRP) were purchased from BD Biosciences PharMingen (San Diego, CA). The mouse monoclonal antibodies c-Met, phosphotyrosine (PY) clone 4G10, the phosphorylated form of Akt (Ser 437), the rabbit polyclonal antibodies against the p85α subunit of PI-3K, and the phosphorylated form of Met (Tyr 1234, Tyr 1235) were purchased from Upstate (Charlottesvile, VA). The rabbit polyclonal antibodies PTP1B, SHP-2, ERK1, the mouse monoclonal antibody of the phosphorylated form of p70S6K at Ser411, the mouse monoclonal PTEN and GAPDH antibodies, the PTP1B substrate, and the protein A or G agarose were from Santa Cruz Biotechnology (Santa Cruz, CA). The rabbit polyclonal antibody SHP-2 in its phosphorylated form at Tyr542 and the biotinylated protein marker detection kit were from Cell Signaling Technology (Beverly, MA). The mouse monoclonal active form of ERK1/2, sodium orthovanadate (SOV), and phenyl arsine oxide were purchased from Sigma-Aldrich (St. Louis, MO). Inhibitors bpV(phen), LY294002, and wortmannin were from Calbiochem (La Jolla, CA). Another peptide inhibitor was purchased from Biomol (CinnGEL 2Me; Plymouth Meeting, PA). Validated PTP1B siRNA, validated SHP-2 siRNA, negative siRNA 1, and siPORT Neo FX transfection reagent were purchased from Ambion (Austin, TX). Mouse monoclonal (RL90) to protein disulfide isomerase (PDI), an endoplasmic reticulum (ER) marker, was from Abcam (Cambridge, MA). Secondary antibodies used for immunostaining, goat anti-rabbit Alexa Fluor 488 and goat anti-mouse Alexa Fluor 546, were from Invitrogen (Carlsbad, CA).