Ras GTP complex. Computer model showing the structure of a molecule of a Ras oncogene protein in complex with GTP (guanosine triphosphate, spheres). Ras proteins are involved in transmitting signals within cells. They are GTPase enzymes - they bind and hydrolyze GTP. Mutations in the Ras gene are an essential step in the development of many cancers, therefore this protein is classed as an oncogene protein. Ras inhibitors such as benzamidine are being studied as a treatment for cancer.