You Are Interested in Further Understanding the Signal Transduction Pathway

Multiple Choice

You are interested in further understanding the signal transduction pathway that controls the production of Pig1, a protein important for regulating cell size.Activation of the TRK receptor leads to activation of the GTP-binding protein, Ras, which then activates a protein kinase that phosphorylates the SZE transcription factor.SZE only interacts with the nuclear transport receptor when it is phosphorylated.SZE is a gene activator for the Pig1 gene.This pathway is diagrammed in Figure 16-25. Figure 16-25
Normal cells grown under standard conditions (without ligand) are 14 μm in diameter while normal cells exposed to TRK ligand are 10.5 μm in diameter.Given this situation, which of the following conditions do you predict will more likely lead to smaller cells?

A) addition of TRK ligand and a drug that stimulates the GTPase activity of Ras
B) addition of TRK ligand and a drug that inhibits the activity of the phosphatase that acts on SZE
C) addition of TRK ligand and a drug that stimulates the degradation of Pig1
D) addition of TRK ligand and a drug that inhibits Pig1 binding to DNA