[Campbell Biology P.268] Which statement accurately characterizes Receptor Tyrosine Kinases ... | Practice Question

Which statement accurately characterizes Receptor Tyrosine Kinases RTKs and their signaling capabilities compared to G protein-coupled receptors GPCRs ?

  • A: RTKs typically activate only a single specific signal transduction pathway, similar to most GPCRs.
  • B: RTKs function by transferring phosphate groups from GTP to serine or threonine residues of substrate proteins.
  • C: Abnormal RTK function, even in the absence of signaling molecules, is associated with various types of cancer due to uncontrolled cell growth signals.
  • D: The intracellular tail of an inactive RTK monomer contains an alpha helix, which is the primary site for ligand binding.

Explanation

RTKs are known for activating multiple downstream signal transduction pathways and cellular responses, a key difference from GPCRs which typically activate only one. Moreover, abnormal RTK function, often due to mutations that cause them to be constitutively active even without a ligand, is a well-established cause of many cancers.