Signal transduction, or cell signaling, is the process by which various signals are transmitted throughout the cell in a cascading series of extracellular and intracellular molecular events involving lipids, proteins, and ions. Often it involves a signal from a secreted growth factor, hormone or other extracellular signaling molecule with binding to receptors at the cell surface, including receptor tyrosine kinases and G-protein coupled receptors, which then transduce the signal intracellularly. A wide range of antibodies are involved in signal transduction, such as cell surface receptor and kinase antibodies, intracellular kinase and adaptor protein antibodies, phosphatase antibodies, and secreted growth factor antibodies. Signaling pathways and their fluid dynamic processes can be studied by researchers aiming to learn more about their far-reaching morphological effects and especially their influence on the regulation of gene expression. Signal transduction antibodies can also offer insight into various pathways and their role in the development of diseases, for example, Alzheimer’s, lupus, cancer and rheumatoid arthritis.