Phosphor tyrosine

HepG2 cells were obtained from the American Type Culture Collection (ATCC, Manassas, VA, USA) and cultured in Dulbecco’s modified Eagle’s medium (DMEM; Hyclone, Logan, UT, USA) containing 10% fetal bovine serum (FBS; Hyclone) and 1% of 100 units/ml of penicillin/streptomycin, and incubated at 37 °C in a humidified 5% CO₂ incubator. Human C1q was obtained from Quidel (San Diego, CA, USA), Collagen I (endotoxin <1.0 EU/ml) from Advanced BioMatrix, Inc. (San Diego, CA, USA), serum free Opti-MEM from Invitrogen (Invitrogen, CA, USA), and WelFect-EX PLUS Transfection Reagent from Welgene (Welgene, Seoul, South Korea). Trizol reagent and the Superscript III kit were obtained from Invitrogen (Invitrogen, CA, USA). Radioimmunoprecipitation (RIPA) buffer, rabbit and mouse secondary antibodies, DDR1 antibody (sc-532), and anti-β-actin antibodies were obtained from Santa Cruz Biotechnology (Santa Cruz, CA). Total and/or phosphorylated-p38, -JNK, -ERK, -PI3K, -Akt, phosphor-tyrosine, and ERK antibodies were purchased from Cell Signaling. C1q antibody (ab71940) was obtained from Abcam (Cambridge, UK), and anti-Phospho-DDR1 (Y513) Antibody (P00905) from Bosterbio (California, USA). Control and DDR1 siRNA were from Santa Cruz Biotechnology (Santa Cruz, CA), and primers from Genotech (Daejeon, Korea). All other reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA).