Autophagosomelike

Autophagosomelike is a descriptive term used in cell biology to refer to intracellular vesicles that resemble autophagosomes in morphology or molecular features but are not unequivocally canonical autophagosomes. The term appears in studies of noncanonical autophagy, atypical autophagic compartments, or pathogen- and stress-induced membrane structures that mimic autophagosomes.

Morphology and markers

Autophagosomelike structures typically present as double-membrane vesicles that enclose cytoplasmic cargo. In canonical autophagy, autophagosomes are characterized by specific conjugation systems, such as LC3/ATG8 on the membrane. Autophagosomelike vesicles may display LC3/ATG8 labeling and can contain cargo and cargo receptor proteins, but their full complement of Atg core components or their dependence on canonical autophagy machinery may differ. Depending on maturation status, they can bear endosomal or lysosomal markers, or they may lack them altogether.

Biogenesis and context

These structures can arise from multiple cellular sources, including endoplasmic reticulum, mitochondria, Golgi, or endosomal pathways, and may form under conditions of stress, infection, or genetic perturbation of normal autophagy. They may represent intermediates, off-pathway compartments, or alternative degradation routes that resemble autophagosomes without fulfilling all criteria of canonical autophagy.

Function and interpretation

Autophagosomelike vesicles are studied to understand noncanonical autophagy, selective autophagy variants, and the interplay between autophagy and other trafficking pathways. Their functional role—whether they participate in cargo degradation, signaling, or immune processes—can vary by context and often requires additional flux assays and marker analyses to interpret.

Terminology note

Because the term is not strictly standardized, the designation should be clearly defined within each study, including details on membrane structure, marker composition, and dependence on canonical autophagy components.