Question

How eukaryotic cells communicate? Describe the mechanism of G-coupling protein receptors with diagrams.

Answer 1

Eukaryotic cells communicate through signalling.There are different type of signalling endocrine, paracrine , autocrine and juxtacrine.

These signalling occur when a ligand bind to the receptor and conformation changes occur in the receptor which further activate the other signal molecule and produce secondary messenger which activate the different protein kinase.

G protein coupled receptor is the cell surface receptors. When the ligand bind to the receptor conformation changes occur in receptor as a result GTP bind to the alpha subunit of G protein . After GTP binding alpha subunit get dissociate from the G protein trimeric subunit. Active alpha subunit bind to adenyl cyclase enzyme which is bound to the membrane and synthesized the cAMP from the ATP . cAMP bind to the regulatory subunit of protein kinase A . Protein kinase A get activated and dissociation of regulatory and catalytic subunit occur as a result catalytic subunit enter the nucleus and phosphorylate the target protein.