Pathways to Cancer: To the Nucleus

Many signaling pathways ultimately pass messages to the nucleus of a cell. The Raf protein (shown in white) activates another messenger protein (in brown) as it passes through fibers that make up the cell's cytoskeleton. The signal is passed to yet another messenger (in purple). These messenger proteins are known as kinases, enzymes with the ability to activate other proteins through the addition of phosphate groups. This protein travels to the nucleus past cellular organelles such as the mitochondria (in glowing orange) and the network of membranes known as the endoplasmic reticulum (shown in light brown).