Question

If a cell developed a mutation in its MAP2K1 gene (encodes the MEK protein) that prevented MEK from being recognized by phosphatases, how would the EGFR signaling cascade and the cell’s behavior change?

Short answer

The cell will continue to replicate and be resistant to apoptosis.

Step-by-step solution

Step 1. Introduction

The cell has a mutation in its MAP2K1 gene that encodes for the MEK protein and now this inhibits MEK from being identified by phosphates.

Step 2. Explanation

EGF binding to EGFR (Epidermal growth factor receptor) would start a signaling cascade which in turn activates the protein kinases through phosphorylation. Active Raf phosphorylates MEK activates the kinase MEK. If dephosphorylation of MEK is not done then signaling cascade downstream of MEK would continue to be active even when the EGF signal is gone. As a result, the cell keeps replicating and becomes resistant to apoptosis (cell death).