Phosphatidylserine

Question 1

phosphatidylserine is essential for blood coagulation

Answer 1

ya

Question 2

what is the role of floppase?

Answer 2

if it sees phos. choline or sph on the inner leaflet, it’ll flop it into the outer leaflet

Question 3

what is the role of a flippase?

Answer 3

sees phos. serine or phos. ethanolamine on outer leaflet, will flip to inner leaflet

Question 4

what is scott syndrome, symptoms, treatment, cause?

Answer 4

extremely rare (3 reported cases); bleeding disorder, clots can’t form; no clinical symptoms; treatment: blood transfusion; conversion of prothrombin to thrombin which is defective (coagulation factors are normal however); PS not being moved from inner to outer–>defect in TMEM16F

Question 5

what is the role of scramblase?

Answer 5

increase in Ca (from vessel damage–>coagulation cascade activated) in the cell activates scramblase–works nonspecifically, but basically flips any p. lipids it finds on inner to outer and outer to inner–>will result in a net increase of PS in the outer leaflet

Question 6

what is TMEM16F?

Answer 6

present in plasma membranes; cation channel–nonselective; doesn’t allow Ca through when defective–>can’t activate scramblase

Question 7

how is prothrombin converted to thrombin?

Answer 7

Factor X comes in and associates with Factor VIIIa and IXa; which will convert X to Xa only with the help of PS; factor Xa can hen interact with factor Va to cleave prothrombin to thrombin

Question 8

when TMEM16F is incorrectly spliced, results in a premature stop codon at the 3 IM domain–> non-functional

Answer 8

ya