Question

Place the following events in Receptor Tyrosine Kinase signaling in order from the point when the RTK binds it ligand.

A.) An SH2 domain proteins is recruited to phosphotyrosine residues

B.) cytoplasmic tails of the RTKs cross-phosphorylate

C.) RAS-GEF catalyzes GTP exchange on RAS

D.) Receptors dimerize in the plasma membrane

Answer 1

Answer:

D.) Receptors dimerize in the plasma membrane----> B.) cytoplasmic tails of the RTKs cross-phosphorylate ---> A.) An SH2 domain proteins is recruited to phosphotyrosine residues ---> C.) RAS-GEF catalyzes GTP exchange on RAS

Reason:

Receptor tyrosine kinase (RTK) activity:

Initially tyrosine receptors dimerize in the plasma membrane followed by cytoplasmic tails of the RTKs cross-phosphorylation. An SH2 domain proteins is recruited to phosphotyrosine residues followed by RAS-GEF catalyzes GTP exchange on RAS for down stream signaling.

SH2 domain: These are structural sulfhydryl domains located in the protein structures of the receptor tyrosine kinases and mediate signaling through binding to P-tyrosine on receptor tyrosine kinases. They have Src homology.

Significance of SH domains: These domains found in the enzymatic proteins including adaptor molecules and in scaffolding protein molecules, which enable signal transduction by binding to P-tyrosine units of the substrate in a specific sequence.