Localization and regulation of yeast aldehyde dehydrogenase Ald4p structures

Previously, we identified yeast strains, namely SWORD, showing more robust Ald4p-GFP filament formation than the typical <i>ALD4::GFP</i> strains. Here, we report that Ald4p-GFP in SWORD strains favorably polymerize into gigantic structures in the cytoplasm, despite the enzyme being established as a mitochondrial resident. In addition, we have found that nocodazole, a microtubule destabilizer, has no effect on Ald4p high-order assembly, suggesting no direct association between microtubule dynamics and Ald4p structure formation. Ald4p assembly cannot be induced by sodium azide treatment, indicating that ATP is not a primary effector of Ald4p polymerization. Interestingly, addition of exogenous acetaldehyde, a substrate of the enzyme, can significantly enhance the structure formation of Ald4p, implying that structure formation may be related to enzymatic activity.