Lecture 3--cell signaling

G protein coupled receptors loops on the outside can

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: th inside and outside of membrane many sgnals Largest family of cell surface receptors. Mediate responses to an enormous diversity of extracellular signals including: hormones, local mediators and neurotransmitters. G-protein linked receptors in general consist of a single polypeptide chain that passes 7 times through the lipid bilayer. not flat in membrane, budle together like this, crystal structure of rhodopsin with retinal insisede it G proteins disassemble into two signaling hetreotrimeric g proteins; got three units when activatedcomponents, and hetero means three different components forming a complex; gtpas but not g protein Inactive state: Both receptor and G protein are inactive and not bound the trimer; alpha is a gtpase. normally whe no sgnal, the alpha, beta and gamme bound together with alpha boud to gdp; when signal compes and interactw with membrane recpeto, translocates, the trimer interactw tith receptor, makes it change comformation, akpha subunit releases gdp and attaches to gtp, making it active, beta and gamma remain bound but detach from rest, alpha and TP stay bound but deslocate from the receptor Activation of receptor: G protein associates with the receptor the trimer does not have a transmembrane domain but is associated with membrane, how?linked to lipids alpha and gamma protein linked to lipid Activated G protein: Binding to the activated receptor enables the a subunit of the G protein to exchange its G...
View Full Document

This note was uploaded on 02/23/2014 for the course MCDB 165A taught by Professor Iruela-arispe during the Winter '08 term at UCLA.

Ask a homework question - tutors are online