Question

1) Describe what would happen with vesicle transport in cells incubated with a non-hydrolysable form of GTP. You get extra points if you describe (correctly) a third one. 2) Tumor cells display a more glycolytic metabon where secrete lactic acid secrete, which in turn acidifies the media. At the same time you do an experiment and you find that these cells decrease their cholesterol uptake. a) describe what that experiment could be. b) how do you explain these results? c) what would you do to test the effect of tumor cell metabolism in cholesterol uptake?

Answer 1

1. Vesicle transport means the budding of the vescicle from the membrane which carry a specific protein. the membrane may be endoplasmic reticulum,plasma membrane.etc and transport and fuse to the target membrane where protein is needed. During this vesicular trafficking some needs GTPases and other proteins. which is responsible for fusion,some require hydrolysable GTP as a source for activity example Rab proteins .because of the incubation of  non hydrolysable form of GTP. they stop the budding of vesicles so there is no transport no fusion.

the process is explained below:

Rab [G-protein] a membrane protein activates only along with GTP carry the molecules and comes out from the membrane(budding)  and interact with tethering protein uncoat the vesicle and fusion to target membrane takes place. The non hydrolysable GTP a inhibitor goes and binds to Rab protein so there is no further transport because of inactivation.

2.a)The experiment could be a cancer metabolic reprogramming

b)where usually the glycolysis takes place in normal cells in limited oxygen conditions due the mutation in mitochondrial genes cause decreased mitochondrial oxidation will give rise to exposure of high oxygen more glucose production due to which more lactic acid production and normal cells take up outside cholesterol and synthesize the lipid membrane.where as cancer cells cannot uptake they prepare own cholesterol by moving the steroid receptors to the nucleus and production of more cholestrol.

Therefore the glucose levels are high in cancer cells as well as cholesterol uptake is low that the eflux is decreased and influx of cholestrol is increased.

c)i would have  done a tumour cell metabolic imaging where can easily find out the cholestrol metabolism as well as other metabolic process.