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A total of 16 µl pure protein lysate of the sample with the lowest concentration was used. A comparative amount of protein lysate from the other samples was diluted in water (in all 16 µl volume) and used. These samples were mixed with sample buffer (6.25 µl) and reducing agent (2.5 µl), incubated at 70°C for 10 min, and centrifuged for 1 min at 11,000 × g. 20 µl of each sample were loaded onto a 4–12% polyacrylamide NuPage Bis-Tris gel (Invitrogen). Electrophoresis was running for 1 h at 200 V and 120 mA using the XCell SureLock system (Invitrogen). The transferring of the separated proteins to nitrocellulose membranes (Invitrogen) was done with the iBlot kit and system (Invitrogen) following the manufacturer´s instructions. Blocking of the membrane was carried out with 5% nonfat milk powder (Roth) in TBST (0.1% Tween 20) at room temperature for 1 h and probed with mouse polyclonal antibody 57934 against human ADAM9 (Abcam) at a dilution of 1:500 in TBST (GE Healthcare UK Limited) and with γ-tubulin antibody T6557 in a dilution of 1:5,000 in TBST (Sigma). The secondary antibody, sheep anti-mouse IgG-HRP NA931V (Amersham), was diluted in TBST (1:1,000). For protein detection the ECL Western Blotting Analysis System (Amersham) was used. Visual analysis was performed by two independent investigators, evaluating the presence or absence of specific protein bands.