Lecture 20-Signal Transduction Flashcards
Cell surface Receptor characteristics (5)
Examples too
- Hormone hydrophilic
- Extracellular domain for binding hormone/signal
- Intracellular domain for signal transduction
- Use of second messengers
-
RAPID RESPONSE
Examples: peptide-hormones (insulin, glucagon, epi, Acth, GABA, Eicosanoids)
Intracellular Receptors characteristics (6)
Examples too
- Lipophilic/hydrophilic signals difuse through plasma membrane
- Located in nucleus
- Conformational change on binding hormone
- Bind to specific regions of the DNA
- Gene expression
-
SLOW RESPONSE
Examples: Steroid hormones, thyroxine, Vit. A,D
What are the two examples of Autocrine signaling?
- Growth Factor
- Eicosanoids
What are the 4 examples of Paracrine signaling?
- Neurotransmitters
- Growth Factors
- Eicosanoids
- NO
What are the 4 examples of Paracrine signaling?
- Neurotransmitters
- Growth Factors
- Eicosanoids
- NO
Are receptors specific or are hormones specific for a type of cell?
Receptors are specific. A hormone can bind to more than 1 type of receptor
Examples of steroid and thryoid receptor family (7)
- Testosterone
- Estrogen
- Cortisol
- Aldosterone
- Vit. D
- Vit. A
- Thyroid hormone
Examples of Ligand gated signaling molecules (4)
- Nicotinic ACh receptors
- Glutamate receptors (Ionotropic)
- GABA-A receptors
- Glycine receptors
What is an example of a Catalytic receptor (receptor enzyme)
Insuline Receptor Tyrosine Kinase
Action: binding of ligand (insulin) ATP cleavage and autophosphorylation
Action steps of GLUT 4 (6)
- Insulin binds to extracellular receptor
- GLUT 4 translocation from Golgi to plasma membrane
- Vesicle containing GLUT 4 binds and fuses to plasma membrane
- Glucose transport allowed in response to insulin
- Insulin dissociates from receptors (inactivation)
- Vesicles containing GLUT 4 translocated back to Golgi for storage
Examples of 2nd messengers (4)
- Adenylate cyclase system produces cAMP
Calcium phsphatidylinositol system produces: - Ca 2+
- IP3
- DAG
When GDP is binded to G protein is it activated or deactivated?
Deactivated
G alpha q activates what?
Alpha 1 adrenergic receptor
Activates phospholipase C
Increases: IP3, DAG, Ca2+
G alpha i does what?
Alpha 2 adrenergic receptor
Inhibits adenylate cyclase
Decrease cAMP levels
G alpha s does what?
Beta adrenergic receptor (glucagon)
Activate adenylate cyclase
Increase cAMP levels