Total cell protein extracts were separated on 10% or 15% SDS–PAGE and transferred onto polyvinylidene fluoride (PVDF) membranes. The membranes were subsequently probed with indicated primary antibodies and anti-mouse or anti-rabbit secondary antibodies, respectively. All of the first antibodies were diluted at 1:1000 except for Actin at 1:5000. The chemiluminescence signal was detected with Luminescent Image Analyzer LAS-4000 (Fujifilm). Blotting membranes were stripped and reprobed with anti-Actin as a loading control.