The Raf family of serine/threonine-specific kinases is comprised of three members (A-Raf, B-Raf, and c-Raf) that play a critical role in regulating cell growth and differentiation, and couple growth factor receptor stimulation to nuclear transcription factors via the Ras/mitogen-activated protein kinase (MAPK) pathway. c-Raf kinase (also known as Raf-1) is a key 74 kDa signal transducer of multiple extracellular stimuli that is regulated by several pathways, and that once activated, phosphorylates MEK which in turn phosphorylates ERK. Activation of Raf kinase activity is induced by several events including phosphorylation at several sites and binding of GTP-bound Ras and/or 14-3-3 proteins. The c-Raf antibody is useful as a positive control and for measuring total c-Raf protein levels to compare signals obtained with the c-Raf PSSAs.