help! The protein B-Raf is mutated in about 20% of colorectal cancers. It is an

Question

help!

The protein B-Raf is mutated in about 20% of colorectal cancers. It is an essential protein that functions in a growth factor signaling cascade. B-Raf is normally activated by phosphorylation of specific amino acids such as threonine, serine, and tyrosine. The cancerous mutations result in a B-Raf that is constitutively active. In one sample of cancerous cells you notice that a tyrosine has been mutated to a glutamate. Why do you think a tyrosine mutated to glutamate is constitutively active?

Explanation / Answer

Yes, if tyrosine is mutated to glutamate then B-Raf gene is constitutively active as it  allows activation of this signaling cascade in the absence of any extracellular stimuli, allowing the cell to become self-sufficient in growth signals within this pathway.

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