[Campbell Biology P.268] Once a Receptor Tyrosine Kinase RTK dimer is fully activated throug... | Practice Question

Once a Receptor Tyrosine Kinase RTK dimer is fully activated through autophosphorylation, what is the immediate subsequent step in the signal transduction pathway leading to a cellular response?

  • A: The activated RTK dimer directly enters the nucleus to bind to DNA and alter gene expression.
  • B: Specific inactive relay proteins inside the cell bind to the phosphorylated tyrosines on the RTK, undergoing a structural change that activates them and triggers a transduction pathway.
  • C: The RTK dimer rapidly dissociates back into individual monomers, each capable of initiating a unique cellular response.
  • D: The receptor releases phosphate groups back into the cytoplasm to be recycled for ATP synthesis.

Explanation

Once an RTK dimer is fully activated by autophosphorylation meaning it has multiple phosphorylated tyrosines , these phosphorylated tyrosines serve as binding sites for specific relay proteins. The binding of these relay proteins induces a conformational change in them, activating them and thereby initiating various signal transduction pathways that lead to diverse cellular responses.