A gain of function mutation to a gene encoding a protein in a signal transduction pathway
A) cannot involve the genes encoding heterotrimeric guanine nucleotide-binding proteins.
B) causes constitutive activation of signal transduction.
C) is characterized by a measurable increase in the circulating concentration of the specific hormone agonist.
D) is invariably germ?line in origin.

Question

Quizplus · Accepted Answer

A gain of function mutation to a gene encoding a protein in a signal transduction pathway causes constitutive activation of signal transduction. It means that the mutated protein becomes active without the need for a signal from outside the cell. This can lead to uncontrolled cell growth and division, which can result in diseases such as cancer. Heterotrimeric guanine nucleotide-binding proteins, also known as G proteins, are not the only proteins involved in signal transduction pathways, so a gain of function mutation can involve other genes. The circulating concentration of the specific hormone agonist may or may not be affected by the mutation. Gain of function mutations can occur in either germ-line or somatic cells.

A Gain of Function Mutation to a Gene Encoding a Protein