Loading Control Antibody Sampler Kit (HRP Conjugate) #4670

Housekeeping proteins perform numerous basic functions within the cell and are constitutively expressed at high levels in a variety of tissues and cell types. Western blot analysis commonly uses housekeeping proteins such as β-actin, COX IV, GAPDH, histone H3 and the α- and β-tubulins as loading controls. Actin is a ubiquitous protein and a major component of the eukaryotic cytoskeleton. Actin exists mainly as the F-actin fibrous polymer (1). Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the phosphorylation of glyceraldehyde-3-phosphate during glycolysis. Recent work has demonstrated that GAPDH plays roles in apoptosis (2), gene expression (3), and nuclear transport (4). Globular tubulin subunits made up of α- and β-tubulin heterodimers are the building blocks of microtubules, one of three types of cytosolic fibers that comprise the cytoskeleton (5). Histone proteins, including histone H3, make up the primary building block of chromatin known as nucleosomes. Modulation of the chromatin structure plays an important role in the regulation of transcription in eukaryotes (6). Cytochrome c oxidase (COX) is a hetero-oligomeric enzyme consisting of 13 subunits localized to the inner mitochondrial membrane (7-9). It is the terminal enzyme complex in the respiratory chain, catalyzing the reduction of protons across the mitochondrial inner membrane to drive ATP synthesis (10).