|Genes that are constitutively and stably expressed at high levels in almost all tissues and cells are often referred to as “housekeeping” genes. House keeping proteins like GAPDH are useful as loading controls for western blots and protein normalization (1,2). Increasingly, researchers are making use of specific antibodies to housekeeping proteins, like GAPDH, to standardize and compare levels of protein (control for protein loading). For example, IMGENEX’s ready to use western blots, INSTA-Blot™ products, consists of multiple pre-run tissue or cell lysates on multi-lane blots. In our laboratories, the GAPDH antibody (IMG-5019-1 and IMG-5019-2) is used in the quality control testing of each lot of blots. |
In addition to being useful as loading controls, housekeeping proteins can be of interest to researchers in of themselves. The expression or localization of housekeeping proteins can vary under certain conditions. For example, GAPDH has been found to move from the cytoplasm to the nucleus during apoptosis suggesting that one nuclear translocation of GAPDH may play a role in cell death (3).
|Fortun, J., W.A. Dunn, S. Joy, J. Li, and L. Notterpek. 2003. Emerging role for autophagy in the removal of aggresomes in Schwann Cells. J. Neurosci. 23: 10672-10680. (GAPDH, clone 1D4: Western blot, protein loading control).|
Ellis, R.C., J.N. Earnhardt, R.L. Hayes, K.K. Wang, and D.K. Anderson. 2004. Cathepsin B mRNA and protein expression following contusion spinal cord injury in rats. J. Nuerochem. 88:689-697. (GAPDH, clone 1D4: Western blot, protein loading control).
Dastoor, Z and J-L Dreyer. 2001, Potential role of nuclear translocation of glyceradldehyde-3-phosphate dehydrogenase in apoptosis and oxidative stress. J. Cell Sci. 114:1643-1653