Question

You decide to test to see if your hypothesized pathway is correct. You see the following:

• Blocking SH2 domains eliminates all effects of drugs B and C
• Cholera toxin stimulates all effects of drug A
• Blocking IP3 receptors on the ER blocks the short-term effects of drug C
• Blocking PH domains blocks the short-term effects of drug B
• Adding in a RAS GAP prevents the addition of Ca++ channels when A and B are added together.

Draw the most likely signal transduction pathways by which drugs A , B, and C mediate their effects taking this new data into account.

Answer 1

Drug A acts through a G-protein mediated signal transduction pathway. Drug B acts through a receptor tyrosine kinase-mediated signal transduction pathway. Drug C acts through a signal transduction pathway involving IP3 receptors and calcium release from the ER.

Step-by-step explanation:

The most likely signal transduction pathways for drugs A, B, and C, taking into account the given data, can be illustrated as follows:

Drug A:

• Cholera toxin stimulates all effects of drug A, indicating that drug A acts through a G-protein mediated signal transduction pathway.

Drug B:

• Blocking PH domains blocks the short-term effects of drug B. This suggests that drug B acts through a receptor tyrosine kinase-mediated signal transduction pathway.

Drug C:

• Blocking IP3 receptors on the ER blocks the short-term effects of drug C, indicating that drug C acts through a signal transduction pathway involving IP3 receptors and calcium release from the ER.

Based on this information, the most likely signal transduction pathways for drugs A, B, and C are:

Drug A: G-Protein Mediated Signal Transduction by PKA

Drug B: Receptor Tyrosine Kinase-Mediated Signal Transduction

Drug C: Signal transduction pathway involving IP3 receptors and calcium release from the ER.