Lipolysis

Question 1

What is the structure of lipid droplets?

Answer 1

single layer of phospholipids to create a hydrophobic internal environment with proteins on the exterior

Question 2

How were the proteins on the lipid droplets discovered?

Answer 2

centrifuge cells to have lipids on top and through SDS page isolate proteins

Question 3

How were the proteins visualized?

Answer 3

immunofluorescence microscopy

Question 4

What is the most adundant protein in the lipid droplets?

Answer 4

perilipin

Question 5

What is perilipins role?

Answer 5

forms a barrier on droplets to prevent unwanted lipolysis

Question 6

What occurs when lipolysis is activated to the perilipin?

Answer 6

goes through conformational change so lipolysis can occur

Question 7

What was previously believed about lipolysis?

Answer 7

Hormone sensitive lipase was the sole enzyme present in beta oxidation

Question 8

What was the experiment that proved that HSL was not the sole enzyme?

Answer 8

HSL KO mice found that there was an accumulation of DGs instead of TAGs

Question 9

What was the first step in identifying the new lipase?

Answer 9

bioinformatics to find the motif and verify by Northern Blot

Question 10

What is the motif found in all adipose lipases?

Answer 10

Gly-X-Ser-X-Gly

Question 11

Why is the serine so important for the lipase activity?

Answer 11

is the active site

Question 12

What is the enzyme responsible for releasing fatty acids for TAG?

Answer 12

Adipose tissue triacylglycerol lipase

Question 13

What was the last step in the experiment to confirm the role of ATGL?

Answer 13

put fat in test tube and found that TAG not DG was preferred substrate

Question 14

What is the steps of lipolysis?

Answer 14

TAG-DG-MG-Glycerol

Question 15

What are the steps that occur that activate lipolysis?

Answer 15

epineprine or flucagon bind receptor to activate cAMP which activates PKA which activates HSL

Question 16

What is the enzyme that converts DG-MG?

Answer 16

HSL

Question 17

What is the enzyme that converts MG to glycerol?

Answer 17

MGL

Question 18

What is CGI-58 and its role in lipolysis?

Answer 18

CGI-58 interacts with perilipin but during lipolysis it removes itself and activates ATGL

Question 19

What is Chanarin-Dorfman Syndrome?

Answer 19

a mutation in CGI-58 that prevents lipolysis

Question 20

What are the symptoms of Chanarin Dorfman Syndrome?

Answer 20

scaly skin, accumulation of fat in liver, eyes, muscles and ears