Western blot is a widely used method for determining specific protein levels. To correct for protein loading and factors, such as transfer efficiency, an internal control is often used. To date, some housekeeping gene–coded proteins (i.e., β-actin,GAPDH and β-tubulin) are widely used as internal controls in the Western blot analysis. Housekeeping proteins perform numerous basic functions within the cell and are constitutively expressed at levels in a variety of tissues and cell types.