Day 3 - Part 2

What are the three main classes of cell surface receptors

Ion channel coupled receptors G protein coupled receptors and enzyme coupled receptors

What happens in ion channel coupled receptors

Ligand binding opens an ion channel allowing ions to flow

What ions commonly flow through ion channels

Calcium sodium or potassium ions

How fast are ion channel receptor responses

Very fast in milliseconds

What is an example of ion channel receptor function

Neuronal signaling and action potentials

What are G protein coupled receptors

Receptors that activate heterotrimeric G proteins

What happens when a GPCR is activated

The G protein splits into alpha and beta gamma subunits

What do activated G protein subunits do

Activate downstream signaling pathways

What is a key feature of GPCR signaling

Signal amplification

What are enzyme coupled receptors

Receptors that have enzymatic activity or are directly associated with enzymes

What are receptor tyrosine kinases RTKs

Enzyme coupled receptors that phosphorylate tyrosine residues

What happens when a ligand binds an RTK

The receptor dimerizes

What happens after RTK dimerization

The receptors autophosphorylate on tyrosine residues

What is the purpose of RTK autophosphorylation

Creates binding sites for signaling proteins

What binds to phosphorylated RTKs

Adaptor proteins and signaling molecules

What is the first step in the EGFR pathway

EGF binds to the receptor

What is the second step in the EGFR pathway

The receptor dimerizes

What is the third step in the EGFR pathway

Tyrosine residues are phosphorylated

What is the fourth step in the EGFR pathway

Adaptor proteins bind

What pathways are activated downstream of RTKs

Ras MAPK pathway and PI3K Akt pathway

What is the function of the Ras MAPK pathway

Promotes cell proliferation

What is the function of the PI3K Akt pathway

Promotes cell surviva