Experimental Evidence for Conservation of the Ubiquitin-Like Autophagy-Related ATG12 Conjugation System in Trichomonas vaginalis

Abstract

Autophagy, an intracellular degradation system, is mediated by autophagy-related (ATG) factors, including the ubiquitin-like ATG12 conjugation system. While the ATG12 system was previously thought to be lost in Trichomonas vaginalis, we provide experimental evidence for its conservation. Using AlphaFold-based structural analysis and functional assays in heterologous cells, we demonstrated that candidates of the ATG12 system in T. vaginalis mediate ubiquitin-like conjugation reactions. This study fills a knowledge gap in the autophagy molecular mechanisms in protists and suggests a practical approach for analyzing ATG proteins in evolutionary divergent protists that are difficult to culture or genetically manipulate.