Cytokine Receptors

Question 1

Define a cytokine

Answer 1

any class of immunoregulatory proteins that are secreted by cells especially of the immune system

Question 2

Type I/II cytokine receptors are _

Answer 2

Multimeric

Question 3

Multimeric:

Answer 3

• uniqure high-affinity, ligand-binding subunits
• shared signal-transducting subunits > activate intracellular tyrosine kinases

Question 4

What role do cytokines play in the activation of cytokine receptors?

Answer 4

Cytokines bind to their specific receptors, inducing receptor dimerization or conformational changes.

Question 5

Why do cytokine receptors rely on JAKs for signaling?

Answer 5

Cytokine receptors lack intrinsic kinase activity and depend on JAKs to phosphorylate tyrosine residues.

Question 6

What happens after JAKs are activated in the JAK–STAT pathway?

Answer 6

JAKs transphosphorylate each other and phosphorylate tyrosine residues on the receptor.

Question 7

How are STAT proteins recruited to cytokine receptors?

Answer 7

Phosphorylated tyrosine residues on the receptor act as docking sites for STAT proteins via their SH2 domains.