Gapdh western blot kda7/24/2023 GAPDH is highly conserved across species. GAPDH is a housekeeping gene and used as controls in both Western blot and qPCR. The tetramer of GAPDH is involved in glycolysis. Beta-actin is also present in the nucleus, as a component of chromatin remodeling complexes, but it can not be used as a control for nuclear protein samples.įigure 3. Publications have indicated that beta-actin may not be a reliable loading control in Western blot analysis in most cases. Changes in cell growth conditions do disrupt actin protein synthesis. Please see the detailed discussion about beta-actin loading control and commonly used clones, and frequently asked questions about beta-actin controls.Īctin proteins tend to be present in cells at very high concentrations, and thus if this control is used it is essential to ensure that you are working within the dynamic detection range so there is no signal saturation and variation in actin protein levels can be detected.īefore selecting an actin protein as your loading control you should ensure that it is an appropriate control with very little to no variation among your treatment groups. The image is from NIH.īoth beta and alpha actins have been used as loading controls in Western blot experiments. The signal intensity must correlate directly with the protein concentration within the range that will be used in the experiment.įigure 2. The dynamic detection range for a loading control can be determined by running a Western blot specifically for the protein control in serial dilution. That is, the protocol and detection method can reveal the changes in the levels of loading controls and the proteins of interest without signal saturation. the detection limits for the loading controls and the proteins of interest are within dynamic ranges.the detection bands of loading controls must not interfere with those of the protein(s) of interest (i.e., they should have substantially different molecular weights),.the protein levels of loading controls remain constant (relative to the total protein content) under the test conditions (such as across treatments or developmental stages),.The proteins serving as loading controls must fit certain criteria. The number of publications (num) that cites each type of main loading controls with antibodies from each of the major suppliers. Other interesting observations from this survey are discussed in this article later. The results indicate that actin (specifically beta actin) is the most commonly used control. Figure 1 displays the Western blot images compiled from some of those publications. Labome has surveyed publications with loading controls in Western blots (Table 1). Looking to the literature can be very useful in considering potential loading controls for your Western blotting experiments. For this reason housekeeping genes that are constitutively expressed and necessary for basic cell functions, like cytoskeletal proteins, are typically used for loading controls. For any particular experiment it is important to consider potential loading controls and try to find a protein that is expressed at stable levels among the samples of interest. A variety of different proteins are used as loading controls. To use a loading control for these purposes detection with control protein antibody and the experimental antibody should be done on the same blot. The signals from loading controls are typically used to normalize the signals from the proteins of interest. - antibody incubation (for primary or secondary antibody), and signal detection across separate samples/lanes.- protein transfer efficiencies from the gel to the membrane among different samples/lanes,.- the amount of protein sample loaded in each lane,.Ī loading control accounts for potential variation in:
0 Comments
Leave a Reply. |