A transmembrane (i.e., through the cell membrane) protein that is coded for by the ras gene. The ras protein end that is outside the cell membrane acts as a receptor for applicable growth factors (e.g., fibroblast growth factor), and conveys that signal (i.e., to divide/grow) into the cell when that chemical signal (i.e., the growth factor) touches “receptor end” ofthe ras protein. When the ras gene has been damaged or mutated (e.g., via exposure to cigarette smoke or ultraviolet light), that gene causes excess ras proteins to be manufactured, which causes over-signalling of the cell to divide and grow (i.e., cell becomes cancerous).