Lipolysis Flashcards
What is lipolysis
Breakdown of TG stored in adipose tissue to fatty acids and glycerol
Fatty acids are then turned to ATP via B-oxidation in the mitochondria
What are lipases
break down ester bonds of triacylglycerol to release 3 FA
What are lipid droplets? What is the role of LD in adipocytes and structure?
Organelle that contains TG
TG storage in adipocytes
present in cytosol
Surface of phospholipids and proteins
Core of TG
T/F lipid droplet-associated proteins have specific functions
True
What is the most abundant lipid droplet protein
Perilipin
Function of perilipin
Forms a barrier around LDs
Prevents unwanted lipolysis
What is immunofluorescence microscopy
Visualize specific proteins in cells
allows you to see the location of a protein in a single cell
What happens to perilipin when lipolysis is activated
Perilipin undergoes a conformational change
Can access TG
Was the classic pathway of lipolysis correct? Why or why not
No
Though that HSL (hormone sensitive lipase) was responsible for every step from TG to glycerol, when HSL didn’t participate int he first step to DG.
It is a DG lipase
What is HSL
HSL is a DG lipase and is not the lipsae responsible for TG hydrolysis during lipolysis
What accumulates in HSL ko-mice
DG accumulated
All lipases have what motif?
GXSXG
(Serine is important for catalysis)
What was the enzyme that was found to be responsible for the first step of lipolysis?
Adipose Tissue Triacylglycerol Lipase (ATGL)
Where is ATGL present
Adipocytes
What happened in ATGL KO mice
TG lipase activity was reduced by 80%
Lipolysis was impaired