Tubular network formation protects mitochondria from autophagosomal degradation during nutrient starvation

AS Rambold, B Kostelecky, N Elia… - Proceedings of the …, 2011 - National Acad Sciences
AS Rambold, B Kostelecky, N Elia, J Lippincott-Schwartz
Proceedings of the National Academy of Sciences, 2011National Acad Sciences
Mitochondria are highly dynamic organelles that mediate essential cell functions such as
apoptosis and cell-cycle control in addition to their role as efficient ATP generators.
Mitochondrial morphology changes are tightly regulated, and their shape can shift between
small, fragmented units and larger networks of elongated mitochondria. We demonstrate that
mitochondrial elements become significantly elongated and interconnected shortly after
nutrient depletion. This mitochondrial morphological shift depends on the type of starvation …
Mitochondria are highly dynamic organelles that mediate essential cell functions such as apoptosis and cell-cycle control in addition to their role as efficient ATP generators. Mitochondrial morphology changes are tightly regulated, and their shape can shift between small, fragmented units and larger networks of elongated mitochondria. We demonstrate that mitochondrial elements become significantly elongated and interconnected shortly after nutrient depletion. This mitochondrial morphological shift depends on the type of starvation, with an additive effect observed when multiple nutrients are depleted simultaneously. We further show that starvation-induced mitochondrial elongation is mediated by down-regulation of dynamin-related protein 1 (Drp1) through modulation of two Drp1 phosphorylation sites, leading to unopposed mitochondrial fusion. Finally, we establish that mitochondrial tubulation upon nutrient deprivation protects mitochondria from autophagosomal degradation, which could permit mitochondria to maximize energy production and supply autophagosomal membranes during starvation.
National Acad Sciences