Analysis of Autophagic Activity Using ATG8 Lipidation Assay in Arabidopsis thaliana.

As a fundamental metabolic pathway to degrade and recycle cellular cargos, autophagy is highly induced upon stress, starvation and senescence conditions in plants. A double-membrane structure named autophagosome will form during this process for cargo sequestration and delivery into the vacuole. A number of regulators have been characterized in plants, including the autophagy-related (ATG) proteins and other plant-specific proteins. Among them, ATG8 will undergo a lipidation process to become a membrane-bound ATG8-phosphatidylethanolamine form and mark the growing autophagosomal membrane as well as the completed autophagosome. Therefore, ATG8 has been regarded as a marker for autophagosomes; and biochemical detection of the membrane-associated form of ATG8 is used as one of the principal methods for measurement of autophagic activity. Here, we describe an ATG8 lipidation assay for detection of the ATG8-PE form using Arabidopsis thaliana seedlings.