Autophagy in the test tube: In vitro reconstitution of aspects of autophagosome biogenesis

Autophagy is a versatile recycling pathway that delivers cytoplasmic contents to lysosomal compartments for degradation. It involves the formation of a cup-shaped membrane that expands to capture cargo. After the cargo has been entirely enclosed, the membrane is sealed to generate a double-membrane-enclosed compartment, termed the autophagosome. Depending on the physiological state of the cell, the cargo is selected either specifically or non-specifically. The process involves a highly conserved set of autophagy-related proteins. Reconstitution of their action on model membranes in vitro has contributed tremendously to our understanding of autophagosome biogenesis. This review will focus on various in vitro techniques that have been employed to decipher the function of the autophagic core machinery.