mother cell's vacuole move into the bud where they fusewith one another to form a new vacuole. These vesiclescarry both v-SNARES and t-SNARES. Are both types ofSNARES essential for this homotypic fusion event?(B)10075To test this point, you have developed an ingeniousassay for fusion of vacuolar vesicles. You prepare vesiclesfrom two different mutant strains of yeast: strain B has adefective gene for vacuolar alkaline phosphatase (Pase);strain A is defective for the protease that converts the pre-cursor of alkaline phosphatase (pro-Pase) into its activeform (Pase) (Figure Q13-2A). Neither strain has activealkaline phosphatase, but when extracts of the strains aremixed, vesicle fusion generates active alkaline phospha-tase, which can be easily measured (Figure Q13-2).5025strain A vtvtVvtVvtstrain B vtvtvtVvtexperiment 124710 11Now you delete the genes for the vacuolarSNARE combinationsv-SNARE, t-SNARE, or both in each of the two yeast strains.You prepare vacuolar vesicles from each and test them fortheir ability to fuse, as measured by the alkaline phospha-tase assay (Figure Q13-2B).Figure Q13-2 SNARE requirements for vesicle fusion (Problem 13–7).(A) Scheme for measuring the fusion of vacuolar vesicles. (B) Resultsof fusions of vesicles with different combinations of v-SNARES andt-SNARES. The SNARES present on the vesicles of the two strainsare indicated as v (v-SNARE) and t (t-SNARE). (Adapted from B.J.Nichols et al, Nature 387: 199–202, 1997. With permission fromMacmillan Publishers Ltd.)What do these data say about the requirements forv-SNARES and t-SNARES in the fusion of vacuolar vesicles?Does it matter which kind of SNARE is on which vesicle?Please note the two questions in the last paragraph of this are rhetorical (not meant to be answered directly). This is a true/false question:v-SNARES interact weakly with each other.O TrueO Falsealkaline phosphatase(% maximum) (A)strain Astrain Bpro-PaseproteaseDOCKINGpro-PaseproteaseSNARES exist as complementary partners thatcarry out membrane fusions between appropriate ves-icles and their target membranes. In this way, a vesiclewith a particular variety of v-SNARE will fuse only with amembrane that carries the complementary t-SNARE. Insome instances, however, fusions of identical membranes(homotypic fusions) are known to occur. For example,when a yeast cell forms a bud, vesicles derived from themother cell's vacuole move into the bud where they fusewith one another to form a new vacuole. These vesiclescarry both v-SNARES and t-SNARES. Are both types ofSNARES essential for this homotypic fusion event?FUSIONPase(B)10075To test this point, you have developed an ingeniousassay for fusion of vacuolar vesicles. You prepare vesiclesfrom two different mutant strains of yeast: strain B has adefective gene for vacuolar alkaline phosphatase (Pase);strain A is defective for the protease that converts the pre-cursor of alkaline phosphatase (pro-Pase) into its activeLun50ilu25alkaline phosphatase(% maximum)

Question

Accepted Answer

As mentioned SNARES are important for membrane fusion of vesicles.
v SNARES and t SNARES are…