10-13 Research Applications Phosphospecific antibodies are now key tools in researching signal transduction pathways, apoptosis, translation and transcription control, cell cycle regulation, and cytokine signaling pathways. An important attribute of these antibodies is that they do not recognize the unphosphorylated form of their substrate. Therefore, it is common to use both the phosphospecific and nonphosphospecific antibodies in many experiments. The phosphospecific antibody detects the fraction of substrate that is phosphorylated, whereas the nonphosphospecific antibody detects the total amount of the substrate. By using both antibodies researchers can be sure that changes in the phosphorylation state of the protein are not due to changes in the absolute quantity of protein.
Phosphospecific antibodies come in a wide variety of flavors.
A number of vendors sell antibodies against phosphoserine, phosphothreonine, or phosphotyrosine. These antibodies are useful for determining whether proteins are phosphorylated in general, and on which residue. This class of antibody serves two functions in signal transduction research. They can be used to identify phosphorylated substrates, which are indicators of upstream kinase activity. Researchers studying these signaling pathways can therefore study both the kinase and the substrate to better understand activating events.