Question

How does an activated receptor transfer information from a signal into the cell?

Select one:

a. By endocytosis of the signaling molecule with the receptor.

b. Through a conformational change of the receptor.

c. By increased expression of the receptor.

d. None of the other answer choices are correct.

e. More than one of the other answer choices is correct.

Answer 1

Ans.

An activated receptor transfer information from a signal into the cell through a conformational change of the receptor.

for example in GPCR-

Binding of ligand (like epinephrin) induces confirmational changes in the cytosolic domain of the receptor.

which binds to the GDP bound G-alpha subunit, this binding induces confirmatinal changes in the G-alpha subunit and bound GDP is replaced by GTP.

this GTP bound G-alpha binds to the effector (adenylate cyclase) and activates PKA by cAMP.

catalytic subunit of PKA translocates into nucleus and phosphorylates a transcriptio factor in turn this transcription factor induces transcription of target gene.

In receptor tyrosine kinase (RTK)

RTK is generally exist as monomer but after binding of ligand to the extracytosolic domain of receptor causes confirmational change in receptor which causes dimerization and makes it fuctional.

hence this receptor transduces its signal by confirmational change after binding of ligand.

same in almost all signaling receptor their cytosolic domain undergoes to confirmatinal change upon binding of ligand for transferring their signal to the cell.