Measurement of Autophagy by Flow Cytometry

Autophagy activation is characterized by the accumulation of double-membrane autophagic vesicles (autophagosomes) in the cytoplasm. The mere presence of autophagosomes in the cytoplasm does not necessarily indicate an increased level of autophagy, since the blockade of any step downstream of autophagosome formation increases the number of autophagosomes. Therefore, quantitative methods for the detection of cytoplasmic protein turnover should be employed in addition to autophagosome monitoring, to verify increased levels of autophagy. At the present, multiple methods are available for the quantification of autophagy and the identification of autophagosomes. Here, we detail the in vitro methods currently available to detect autophagic cell death by flow cytometry analysis.