Question

Like the Ras protein itself, the various components of the Ras signaling pathway are changed in cancer cells. What might be the biochemical consequence of mutations in the genes coding for (a) Raf and (b) MAP kinase that result in rapid cell division?

Answer 1

One of the most frequent ways in which MAPK is set to overdrive is by a mutation in ras protein.The MAPK/ERK pathway also known as the Ras-Raf-MEK-ERK pathway is a chain of proteins in the cell that communicates a signal from a receptor on the surface of acell to DNA in the nucleus of the cell.Mutations in the KRAS protein are found in about 40 percent of all colorectal cancer cases where as NRAS are less common ,having a frequency of 5 percent.Both in KRAS and NRAS, the most typical mutations are found at codons 12, most of the times, 13 and 61 (the latter being rarely affected). These mutations are sometimes present in early adenomas and in cells with minimal potential to develop a malignancy. However, they arr also thought to enhance the maligansnt behaviour of cells with advanced CRC; both in vitro and animal studies indicate that silencing these muated codons leads to attenuation of the tumourigenic growth properties of the affected cells.