Question

(2/3) Even though the GRB2 lacks intrinsic enzymatic activity, it is an essential component of the epidermal growth factor signaling pathway that activates MAP kinase. What is the function of GRB2? What role do Sh2 and Sh3 domains play in the function of GRB2?

Answer 1

GRB2 is an essential component of the EGF signaling pathway that activates MAP kinase. Its function is to bind to the EGF receptor and recruit other proteins, such as SOS. The SH2 and SH3 domains of GRB2 play a role in its function by recognizing and binding to specific protein motifs.

Step-by-step explanation:

GRB2 is an essential component of the epidermal growth factor (EGF) signaling pathway that activates MAP kinase. Its function is to bind to the EGF receptor and recruit other proteins, such as SOS, to initiate the downstream signaling cascade. This recruitment is facilitated by the SH2 and SH3 domains of GRB2.

The SH2 domain of GRB2 recognizes and binds to phosphorylated tyrosine residues on the activated EGF receptor, enabling GRB2 to be recruited to the receptor. The SH3 domain of GRB2 then interacts with proline-rich motifs on SOS, allowing SOS to be recruited to the receptor complex. SOS then acts as a guanine nucleotide exchange factor for the small GTPase protein, RAS, leading to the activation of the MAP kinase pathway.