Which of the Following is NOT True of the Son

Question

Which of the following is NOT true of the son of sevenless Sos)protein?
A)It is a guanine nucleotide exchange factor GEF).
B)It is a GTPase-activating protein GAP).
C)It is able to activate Ras.
D)It was initially identified in Drosophila melanogaster.
E)None of the above.

Accepted Answer

The statement "It is a GTPase-activating protein (GAP)" is not true of the son of sevenless (Sos) protein. Sos is a guanine nucleotide exchange factor (GEF) that activates Ras by promoting the exchange of GDP for GTP. GAPs, on the other hand, serve to deactivate Ras by accelerating its intrinsic GTPase activity.