Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a well-known housekeeping gene with functions in glycolysis. Many biologists are familiar with the gene and use GAPDH antibodies for a loading control when performing western blots. However, this primarily cytoplasmic protein is an essential metabolic regulator and has been shown to be involved in a variety of cellular processes like DNA repair, membrane fusion, and cell death (1). Cytoplasmic GAPDH exists as a tetramer and normally mediates the formation of ATP and NADH during glycolysis (1). Under oxidative stress GAPDH can be post-translationally modified to regulate cell metabolism (1). Additionally GAPDH has been shown to interact with the cytoskeleton to influence microtubule and actin polymerization (1).
Western Blot: GAPDH Antibody [NB100-56875] - GAPDH served as a loading control specific to the cytosolic fraction in a western blot control fly head samples fractionated into a cytosolic and membrane fraction from postnuclear supernatant (PNS). The blot was probed for Vps13 expression and EGFR was used as a membrane marker while GAPDH was used as a cytosolic marker. Image collected and cropped by CiteAb from the following publication (//dx.plos.org/10.1371/journal.pone.0170106), licensed under a CC-BY license.
Identifying the diverse functions of GAPDH depends on the use of GAPDH antibodies to identify interacting proteins or examine the protein’s subcellular localization. During cell death, nitrosylated GAPDH accumulates in the nucleus where it is thought to facilitate protein degradation by activating a ubiquitin ligase. Mechanistic details of this process were revealed by Leisner et al. from UNC Chapel Hill (2). In order to characterize this unique form of cell death, this group used GAPDH antibodies to monitor nuclear accumulation and post-translational modification following the disruption of common oncogenic pathways (2). Investigations of GAPDH interactions have also revealed roles in membrane trafficking. By performing co-sedimentation assays and performing western blots with the GAPDH antibody researchers showed Rab2, a small GTPase involved in regulation of the secretory pathway, depends on GAPDH in order to bind microtubules (3). The central role of GAPDH in the glycolytic pathway allows it to function as a sensor of cellular stress and respond by activating downstream pathways. In fact the diverse functions of GAPDH all seem to regulate homeostasis at various levels or locations. While GAPDH antibodies are widely used to monitor levels of this constitutive reference protein, the above research demonstrates their importance in investigating basic cellular mechanisms and understanding the diverse functions of GAPDH.
Novus Biologicals offers GAPDH reagents for your research needs including:
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