Your Research Project Involves the Characterization of a Particular Signal

Your research project involves the characterization of a particular signal transduction pathway. Specifically, you have been studying a receptor tyrosine kinase and protein X, which initiates downstream events. You are certain that protein X is part of the signal transduction pathway, but have been unable to identify a direct protein-protein interaction between the receptor tyrosine kinase and the protein X. What should you do next in your attempt to identify a link between the receptor tyrosine kinase and protein X?

A) Try to identify proteins that act downstream of protein X.
B) Try to identify an adapter protein that can interact with both the receptor and protein X.
C) Try to identify a coactivator protein.
D) Confirm the interaction between the receptor tyrosine kinase and its ligand.