Double-membrane, cup-shaped structures destined to become autophagosomes.

Large spherical double-layered structures which function in AUTOPHAGY to engulf intracellular components such as ORGANELLES or pathogens. Their outer membrane then fuses with the LYSOSOME (forming the AUTOLYSOSOME) and the inner membrane and contents are digested by lysosomal HYDROLASES.

Synonyms: Phagophore, Autophagosomes, Autophagosome, Phagophores