Question

What event is usually responsible for terminating signal transduction by RTKs?

A	degradation of the ligand

B	dephosphorylation of the receptor

C	receptor internalization

D	phosphorylation of the receptor

E	acetylation of the receptor

F	none of the above

Answer 1

Correct Answer : C - receptor Internalization

Explanation : Internalization is a receptor- mediated endocytic process. In this process, the cell will binds to its specific receptor protein on the cell surface. It is the ending response in the process of signal transduction by receptor tyrosine kinase(RTK). In this process the Receptor binding protein are activated by ligands and then autophosphorylate the Tyrosine residues. These residues acts as a binding site for CbI . These CbI catalyses attachment of ubiquitine to other receptors and these receptors marked them for Internalization.

The activated receptors and CbI complex either leads to Receptor ubiquination or Internalization or sometimes degraded in the lysosome itself.