Question

The Ras G protein is a key component of a cascade that plays a role in regulating vital activities like cell proliferation and differentiation. What is the name of the cascade?

1) the Ras GEF cascade
2) the Ras-RAF kinase cascade
3) the Ras-MAP cascade
4) the Ras-IP3 kinase cascade

Answer 1

The correct name of the cascade is the Ras-RAF kinase cascade, which is involved in cell proliferation and differentiation. Mutations in Ras preventing GTP hydrolysis and causing uncontrolled cell proliferation are often linked to cancer.

Step-by-step explanation:

The cascade mentioned in the question is known as the Ras-RAF kinase cascade. The Ras protein plays a crucial role in the regulation of cell proliferation and differentiation through this pathway. When Ras is activated, it leads to the stimulation of RAF, which is a kinase enzyme. RAF, in turn, phosphorylates and activates MEK, which then phosphorylates ERK. The activated ERK can then enter the nucleus and initiate cellular responses that can lead to changes in gene expression, affecting growth and differentiation of the cell.

In the context of cancer, the Ras protein can become problematic if it is unable to hydrolyze GTP into GDP due to a mutation. This scenario leads to an unregulated phosphorylation cascade, meaning that Ras continuously signals downstream components to drive cell proliferation, which can contribute to the development of cancer by causing uncontrolled cell growth.

So, the correct answer to the question about the name of the cascade is 2) the Ras-RAF kinase cascade.