Final answer:
False, the C-terminus is not the hotspot for mutations leading to K-ras oncogene activation; rather, specific codons such as 12, 13, and 61 are where these activating point mutations most commonly occur.
Step-by-step explanation:
The statement that the C-terminus is the hottest spot for point mutations leading to the activation of the K-ras oncogene is false. Point mutations that activate the K-ras oncogene are most commonly found in specific hotspots, which are at codons 12, 13, and 61, rather than at the C-terminus of the K-ras protein. These mutations typically result in a gain of function, leading to uncontrolled cell proliferation and cancer. The RAS oncogene plays a crucial role in up to 30% of all cancers by affecting a phosphorylation cascade involved in cell growth and differentiation through the MAP kinase pathway.
Mutations that activate oncogenes like K-ras often lead to the production of a constitutively active protein enabling continuous signal transduction for cell growth and division, which are characteristic features of cancerous cells.