Final answer:
Ras GTPases significantly impact cellular processes such as growth, differentiation, migration, and lipid trafficking by transmitting signals via downstream cascades like the MAP kinase pathway. In certain cancers, dysfunctional GTPase activity of RAS induces uncontrolled cell growth.
Step-by-step explanation:
Ras GTPases are pivotal regulators in the cellular signaling pathways that control various aspects of cell behavior including cell growth, cell differentiation, cell migration, and lipid trafficking. When activated, Ras GTPases bind GTP and subsequently activate multiple downstream signaling cascades such as the MAP kinase pathway, which leads to the transcription of genes involved in cell proliferation and differentiation. However, in some cancers, the GTPase activity of the RAS protein is inhibited, leading to Ras proteins being stuck in an 'on' state, causing constant activation of downstream signaling pathways that contribute to uncontrolled cell growth, which is a characteristic of cancer.