Validating the Expression Consistency of a Housekeeping Protein

Housekeeping proteins (HKP) are typically used as loading controls because it is assumed that the HKP expression level remains consistent across samples. However, there is evidence that HKP expression levels change in many scenarios, including siRNA treatment, cell death, cell differentiation, etc. Therefore, validation of consistent HKP levels under specific experimental conditions is suggested prior to its selection as a loading control. This application note describes how to validate the consistency of HKP expression before the actual western blot experiment is performed.