Cell Receptors
*Insulin vs Glucagon Receptors
- insulin = tyrosine kinase receptor
--> PI3K pathway
--> increases GLUT 4 transporters to the surface
for glucose uptake into cell - glucagon = Gs receptor
--> increase AC and cAMP levels
Receptor Type Mneumonics
Intracellular Receptors:
- "stay IN, watch TV, PET a CAT"
"stay IN, watch TV, PET a CAT"
stay IN = intracellular receptors
T = T3/T4
V = Vitamin D
P = progesterone
E = estrogen
T = Testosterone
C = cortisol
A = Aldosterone
T = T3/T4
intracellular = intracellular
intracellular = intracellular
*Types of Rectors
- Ionotropic receptors = ions go through immediately when ligand/voltage stimulate
- metaboltropic receptors = 2nd messenger system
--> cAMP, cGMP, IP3/DAG/PKC
*Metabotropic Receptors
- G proteins
2nd messenger system
--> cAMP, cGMP, IP3/DAG/PKC
*IonotropicReceptors
- Ionotropic receptors = ions go through immediately when ligand/voltage stimulate
- IONOTROPIC = NICANOTROPIC = Nicotonic Musc receptors allow ions into the cell
--> they are nonspecific
--> allow Na+ and Ca+ in
--> allow K+ leakage out
*G protein Receptors
*Gq Protein receptors
(q = contracting / Ca++)
- "PIP DAGs for PKC... IP3 = INdoPLasmic reticulum"
--> PIP2 = phospholipid from the cell membrane
--> PIP2 makes DAG and release PIP2 also
--> DAG anchors the PKC to the cell membrane and gets it ready for Ca++ binding
--> IP3 = INdoPLasmic reticulum"" = IP3 goes to the INdoPLastic reticulum to release Ca++ to bind to PKC and activate it - 5HT serotonin
- histamine H1
- angiotensin receptor 1
- NE binds to alpha 1 NE receptors
- GDP bound to alpha subunit of (α,β,γ) G protein --> phosphorylated to GTP
- the GTP-Alpha subunit leaves the Gq protein complex and activates the phospholipase C protein
- phospholipase C converts PIP2 from the plasma membrane into both
--> DAG = dyacylglycerol
--> IP3 - DAG prepares PKC = protein kinase C to be activated by anchoring it to the plasma membrane
- IP3 then travels to the sarcloplasmic reticulum to release Ca++
- Ca++ then travels to the PKC and DAG to activate PKC
- together these lead to muscle contraction
*Gi Protein receptors
(i = inhibitory)
- alpha 2 receptors
*Gs Protein receptors
(s = stimulating)
- beta receptors
- glucagon
Glycogen and Insulin and Glucagon
(Glucose Hormone Control)
Notes:
- glycogen is released from stores by the enzyme glycogen phosphorylase
- note that below, no matter the receptor, the activation of glycogen phosphorylase is in the name
--> activated by phosphorylation
--> cAMP + PKA (glucagon + Epi.)
--> inhibited by Tyr. Kinase (insulin) - the opposite is true for glycogen synthase
--> activated by DEphosphorylation (Tyr. Kinase --> protein phosphatase)
*Insulin Receptors
- insulin = tyrosine kinase receptor
--> PI3K pathway
--> increases GLUT 4 transporters to the surface
for glucose uptake into cell
*Glucagon Receptors
- glucagon = Gs receptor
--> increase AC and cAMP levels
Glucagon receptors
Glucagon Example
Notes:
-
Glucagon receptors for Beta blocker overdose case
Notes:
- note that
Clinical Case
