Question

wht are the common features of receptor tyrosine kinase receptors and cytokine receptors?

Answer 1

Receptor tyrosine kinases (RTKs) are cell surface receptors. They have extracellular, transmembrane and cytosolic domain. the cytosolic domain has tyrosine kinase activity. Ligand binding at extracelluar receptor leads to dimerization of receptors and autophosphorylation of tyrosine residues. This starts the signaling cascade.

Cytokine receptors are cell surface receptors.They have extracellular, transmembrane and cytosolic domain. Some cytokine receptors eg. chemokine receptors have multiple transmembrane domain. The binding of ligand to the cytokine induce receptor oligomerisation and activates the signal cascade by recruiting the molecules to the membrane. There is no dimerisation of receptors. They lack intrinsic enzymatic activity.

The major difference between RTKs and cytokine receptors are that RTKs have intrinsic tyrosine kinase activity whereas cytokine receptors do not have any intrinsic enzymatic activity.