[Campbell Biology P.268] Which of the following accurately describes the activation process ... | Practice Question

Which of the following accurately describes the activation process of Receptor Tyrosine Kinases RTKs after signaling molecule binding?

  • A: Two receptor monomers dimerize, and then each monomer phosphorylates tyrosines on its own intracellular tail.
  • B: A single receptor monomer undergoes a conformational change and directly phosphorylates downstream relay proteins.
  • C: Two receptor monomers dimerize, and each activated tyrosine kinase region adds phosphates from ATP to tyrosines on the tail of the *other* monomer.
  • D: The receptor complex directly activates G proteins, leading to a cascade of cellular responses.

Explanation

Upon binding of a signaling molecule, two RTK monomers associate to form a dimer. This dimerization activates the tyrosine kinase regions, which then autophosphorylate the tyrosines on the intracellular tails of the other monomer, using ATP as the phosphate donor. This process fully activates the receptor.