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. 2000 Feb 7;148(3):465–480. doi: 10.1083/jcb.148.3.465

Figure 9.

Figure 9

Figure 9

Vesicle accumulation test and kinetic analysis of prAPI import in the temperature conditional Apg9p mutant. A, Morphological analysis of apg9Δ indicates an import defect at an early step in the pathway. Wild-type (YW5-1B) and apg9Δ (CTD1) cells were grown in YPD (vegetative) or transferred to SD(−N) (starvation) for 3 h in the presence of PMSF (starvation) and examined by DIC (Nomarski) microscopy (Zeiss Axioplan). PMSF inhibits the degradation of autophagic bodies. Under starvation conditions, wild-type cells accumulate autophagic bodies when vesicle breakdown is blocked. However, under the same conditions, apg9Δ cells do not accumulate autophagic bodies, indicating that Apg9p is required for a step before vesicle fusion and release of the autophagic body into the vacuolar lumen. The apg9Δ strain transformed with the APG9 plasmid shows the same result as wild-type (data not shown). B, The apg9ts strain is tightly blocked for prAPI import at nonpermissive temperature. Wild-type (SEY6210) and apg9Δ (JKY007) cells transformed with the apg9ts centromeric plasmid were incubated at 24 and 38°C for 5 min, pulse-labeled for 10 min, and then subjected to nonradioactive chase reactions for the indicated times. Samples at each time point were immunoprecipitated with antiserum to API and resolved by SDS-PAGE as described in Materials and Methods. API-immunoprecipitated bands were quantified by a Molecular Dynamics STORM PhosphorImager and the results are presented in the graph. The percent mature API was determined by dividing the mature API value over the sum of the precursor and mature API values for each time point.