Figure 4.

(A) shi reduces the accumulation of SNARE complexes in comt mutants. 7S complexes from 10 Canton S, comt^ST17, shi^TS1, or comt^ST17 shi^TS1 flies that were given a 20-min 38°C heat pulse were isolated. A reduction in the 7S complex was found in shi flies after exposure to 38°C, whereas comt mutants show a dramatic accumulation of 7S complex. This result is in marked contrast with comt^ST17 shi^TS1 double mutants, which show a less dramatic accumulation of 7S complex after exposure to 38°C. 7S complexes also were isolated from 10 flies of the indicated genotypes after a 10-min heat pulse at 29°C, which was followed by a 10-min heat pulse at 38°C. Inactivation of dynamin before the inactivation of NSF prevents the buildup of 7S complex in shi comt double mutants. (B) Vesicle fusion is required for SNARE-complex accumulation in comt mutants. 7S complexes were isolated from 10 Canton S, comt^ST17 para^TS1, or comt^ST17 flies after a 5-min 38°C heat pulse. Each strain also expressed a GMR-hid transgene to eliminate the contribution of photoreceptor synapses to the 7S assay. para reduced the amount of 7S complex present (compared with both controls and comt mutants) and eliminated 7S accumulation in comt mutants.