lec 35 Flashcards
Insulin site of origin
Beta (B) cells of pancreas
Insulin chemical nature
Protein
Actions of insulin
Stimulates glucose uptake, protein synthesis, and lipid synthesis in various cell types
Enzyme coupled receptor
Step 1
Signal molecule dimerizes the receptor
Dimerization
Joining two identical molecules together
Enzyme coupled receptor
Step 2
Dimerized receptor phosphorylates itself
Enzyme coupled receptor
Step 3
Phosphorylated receptor activates other target proteins
Undoing Enzyme coupled receptor
Getting rid of signal (receptor becomes inactive and Target cells lose phosphates and do not work)
Glucose
Mobile carbohydrates for animals
Glucose increases
After meals
Pancreas
Makes digestive enzymes for guls
Islet cells
Alpha and beta
Alpha islet cells
Release glucagon proteins when blood glucose is low
Glucagon
Binds to receptor that cause glycogen in liver cells to release glucose
Beta islet cells
Release insulin when blood glucose is high
Purpose of insulin signaling
To let other cells in the body know that glucose is high
Insulin is released by
Regulated exocytosis
Insulin receptors
Unusual that subunits are loosely attached but too far to function
Insulin receptors are not a
Tetramer but rather a dimer (
Insulin brings
Subunits together to activate receptor
Phosphorylation occurs to target cells
Responses to insulin comes from
Fat cells and muscle cells
Cells will
in response to insulin
Import and store glucose in plasma membrane
Kinase cascade
Series of kinases used to transport and store glucose in the plasma membrane
Insulin
Glycogen synthase
Activates
Insulin
Glycogen Breakdown
Decreases
Deactivation of insulin
Remove insulin and receptor turns off
Phosphatases will remove phosphate from target cell and turn target cells off
Bringing glucose transporters back into the cell from the membrane is done by
Pinocytosis (gather into a transport vesicle and store them inside)
Diabetes mellitus
Inability to regulate blood glucose
Too little glucose causes
Fainting Hypoglycemia
Too much glucose causes
Organ damage Hyperglycemia
Type 1 diabetes
Problem with insulin (signal)T
Type 2 diabetes
Problem with insulin receptor
Most common causes of type 1 diabetes
Body kills insulin
Type 2 diabetes most common cause
Prolonged overeating
Cells block out insulin
Treating diabetes mellitus
Insulin shots
How to treat diabetes
Monitoring blood glucose
Synthetic insulin
Healthy diet
Edmonton Protocol
Islet cells are placed in liver where they won’t be attacked and can make insulin
For type 1 diabetes