Which of the Following Statements is TRUE

Question

Which of the following statements is TRUE?
A)MAP kinase is important for phosphorylating MAP kinase kinase.
B)PI 3-kinase phosphorylates a lipid in the plasma membrane.
C)Ras becomes activated when an RTK phosphorylates its bound GDP to create GTP.
D)Dimerization of GPCRs leads to Gα activation.

Accepted Answer

PI 3-kinase is responsible for the phosphorylation of phosphatidylinositol lipids in the plasma membrane, creating signaling molecules that promote downstream cellular responses. MAP kinase is phosphorylated by MAP kinase kinase, while Ras becomes activated by the exchange of GDP for GTP, not by RTK phosphorylation. Dimerization of GPCRs can lead to Gβγ activation, but not Gα activation.