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Tyrosine Kinase Associated Receptor and JAK-STAT Pathway

Tyrosine Kinase Associated Receptor

  • The receptor itself has no enzymatic activity.

  • Associate with a separate molecule that has tyrosine kinase activity ⟶ called tyrosine kinase-associated receptor.

  • Kinases that associate with these receptors are:

    • JAK (Janus family)

    • Src family

  • Example: Receptors for:

    • Some cytokines e.g. IL-2 to IL-6

    • GM-CSF

    • Erythropoietin

    • Growth hormone

    • Prolactin

Tyrosine Kinase Associated Receptor vs Receptor Tyrosine Kinase

  • Receptor Tyrosine Kinase is a single molecule that works as a receptor as well as tyrosine kinase.

  • In Tyrosine kinase-associated receptor, the receptor and enzyme are two separate molecules that associate with each other.

  • Despite this difference, they both work in a similar manner.

JAK-STAT Pathway

  • Under resting state: Receptors exist as monomers.

Binding of the ligand with the receptor


Receptors associate to form a dimer


Dimerization increases affinity for JAK


JAKs associate with receptor


JAK get activated


JAKs phosphorylate tyrosine residues on each other and on receptor molecules


Formation of phosphotyrosine residues


STAT (Signal Transducers and Activators of Transcription) binds with phosphotyrosine residues


JAK phosphorylates STAT


STATs dissociate from the receptor and form a dimer


Dimer goes to the nucleus


Regulates gene transcription




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