Question

What are hormone analogs...why are they used as drugs (agonist versus antagonist)? 

What is beta arrestin and what role does it play in regulating GPCRs?

Answer 1

1. Hormone analogs are the small molecular weight compounds that are used as hormonal replacement therapy having same structure  as that of hormones. They modulate the effect of hormones by acting on their respective receptor molecules. Thus used as drugs to get the desired results.

Agonists have same effect as that of their hormone analogs while as antagonists are the medications that have effect opposite to that of the analogue hormones. Example GnRH agonists and antagonists.

2.beta-arrestin protein family are thought to participate in agonist-mediated desensitization of G protein-coupled receptors and cause specific dampening of cellular responses to stimuli such as hormones, neurotransmitters, or sensory signals.

β-arrestins are versatile adapter proteins that form complexes with most G-protein-coupled receptors (GPCRs) following agonist binding and phosphorylation of receptors by G-protein-coupled receptor kinases (GRKs). They play a central role in the interrelated processes of homologous desensitization and GPCR sequestration, which lead to the termination of G protein activation. β-arrestin binding to GPCRs both uncouples receptors from heterotrimeric G proteins and targets them to clathrin-coated pits for endocytosis