although there are no doubts that autophagy promotes cell survival, in multiple physiological
and experimental settings.44 Significantly, some reports indicate that cells presenting features
of ‘autophagic cell death’ can still recover upon withdrawal of the death-inducing stimulus.
45 In most cases described to date in which autophagy is suppressed by genetic knockout/
knockdown of essential autophagy (atg) genes, cell death is not inhibited but rather occurs at
an accelerated pace,15 pointing to the prominent role of autophagy as a pro-survival pathway.
This said, it should be noted that most of these studies have been performed on immortalized
cell lines in vitro and that autophagic cell death rarely affects individual cells in vivo.19,41
Nevertheless, in specific cases, autophagy may participate in the destruction of cells, as a result
of a protracted atrophy of the cytoplasm, beyond a not yet clearly defined point-of-noreturn.
43,46 Thus, direct induction of autophagy by overexpression of the Atg1 kinase is sufficient to
kill fat and salivary gland cells in Drosophila. Interestingly, although Atg1-driven autophagic
cell death entails caspase-dependent mechanisms in fat cells,46 the same does not hold true in
salivary gland cells (which cannot be rescued from Atg1-induced death by p35 expression).43