Which of the following is NOT true about the role of adapter proteins in the activation of Ras by receptor tyrosine kinases?
A)Following dimerization and autophosphorylation of receptor tyrosine kinases,GRB2 and Sos proteins couple to the receptor.
B)GRB2 and Sos proteins couple the receptor to the inactive Ras·GDP complex.
C)GRB2 interacts with Sos via its SH3 domain.
D)Sos acts as a GAP,which helps convert Ras·GDP to active Ras·GTP.

Question

Quizplus · Accepted Answer

Sos does not act as a GAP (GTPase-activating protein) to convert Ras·GDP to active Ras·GTP. Rather, Sos acts as a guanine nucleotide exchange factor (GEF) to facilitate the exchange of GDP for GTP on Ras, leading to its activation.

Which of the Following Is NOT True About the Role