Download Lecture 8 Basics: Organelles Overview: Types of signaling Types of

Lecture 8 Basics: Organelles
Overview:
Types of signaling
1. Intracellular
Definition:
Examples:
2. Cell-cell recognition
Definition
Examples:
3. Local signaling
Definition:
Paracrine
Synaptic
Types of receptors
4. Hormone Signaling:
Definition:
Examples:
Three steps to signaling:
Four Receptor Types
G protein-coupled receptor
Example:
Steps in receptor response: (summarize figure legend in your own words)
1.
2.
3.
4.
Receptor Tyrosine Kinase:
Kinase definition:
Difference from G protein-coupled receptor:
Example:
Steps in response:
1.
2.
3.
4.
Ligand gated ion channels
Action:
Example:
Steps in response:
1.
2.
3.
Intracellular receptors
Found:
Common ligands:
Location of action:
Steps in response:
1.
2.
3.
4.
5.
Class Notes
Summary table:
Signaling types:
Signaling type
Short or long
distance
Signal enters
cell?
Example
Binding of a ligand to a ligand gated ion channel:
A. Causes a conformational change in the protein
B. Allows ions to flow across the membrane against their concentration
gradients
C. Causes the movement of a G-protein
D. Results in the hydrolysis of ATP
E. Both A and B
Example: G protein-coupled receptor and cholera toxin
Normal digestion:
1.
2.
3.
4.
5.
Regulatory hormone binds to a g protein-coupled receptor
Changes the shape of the receptor, alpha unit releases GDP and binds GTP
Active alpha activates adenylyl cyclase, which produces cyclic AMP
cAMP activates protein kinase A (PKA) to add a phosphate to CFTR channel
Channel opens, chloride exits, water follows, extra fluid aids breaking down
of food
6. Bound GTP on alpha subunit of g protein breaks off phosphate, becomes
inactive very quickly
7. Fluid secretion stops
Cholera Toxin
1. Cholera toxin binds to a glycolipid and injects a protein into the cell
2. The toxin forces a molecule to bind to the alpha subunit that blocks the GTP
in place