Characterization of macroautophagic flux in vivo using a XXXX -based assay.

@entity19 @entity22227 @entity73020 @entity14630 @entity73021 @entity33688 @entity18133
Macroautophagy is a highly conserved catabolic process that is crucial for organ homeostasis in mammals. However, methods to directly measure macroautophagic activity (or flux) in vivo are limited. In this study we developed a quantitative macroautophagic flux assay based on measuring @entity33688 protein turnover in vivo after administering the protease inhibitor @entity14630 . Using this assay we then characterized basal macroautophagic flux in different @entity19 organs. We found that the rate of @entity33688 accumulation after @entity14630 treatment was greatest in the liver and lowest in spleen. Interestingly we found that @entity22227 , an @entity33688 / @entity33688 homologue and the @entity33688 -interacting protein @entity18133 were degraded with similar kinetics to @entity33688 . However, the @entity33688 -related proteins @entity73020 and @entity73021 were not rapidly turned over in @entity19 liver, implying that different @entity33688 homologues may contribute to macroautophagy via distinct mechanisms. Nutrient starvation augmented macroautophagic flux as measured by our assay, while refeeding the animals after a period of starvation significantly suppressed flux. We also confirmed that beclin 1 heterozygous @entity19 had reduced basal macroautophagic flux compared to wild-type littermates. These results illustrate the usefulness of our @entity14630 -based assay for studying the dynamics of macroautophagy in @entity19 .
