Plasma membrane contributes to the formation of pre-autophagosomal structures

Abstract

Both endoplasmic reticulum and mitochondrial membranes are thought to contribute to the formation of autophagosomes during autophagy induction. We now learn that plasma membrane is also involved, and is partly targeted to the growing autophagosome through clathrin-mediated endocytosis. Autophagy is a catabolic process in which lysosomes degrade intracytoplasmic contents transported in double-membraned autophagosomes. Autophagosomes are formed by the elongation and fusion of phagophores, which derive from pre-autophagosomal structures. The membrane origins of autophagosomes are unclear and may involve multiple sources, including the endoplasmic reticulum and mitochondria. Here we show in mammalian cells that the heavy chain of clathrin interacts with Atg16L1 and is involved in the formation of Atg16L1-positive early autophagosome precursors. Atg16L1 associated with clathrin-coated structures, and inhibition of clathrin-mediated internalization decreased the formation of both Atg16L1-positive precursors and mature autophagosomes. We tested and demonstrated that the plasma membrane contributes directly to the formation of early Atg16L1-positive autophagosome precursors. This may be particularly important during periods of increased autophagosome formation, because the plasma membrane may serve as a large membrane reservoir that allows cells periods of autophagosome synthesis at levels many-fold higher than under basal conditions, without compromising other processes.

Cite this article

Ravikumar, B., Moreau, K., Jahreiss, L. et al. Plasma membrane contributes to the formation of pre-autophagosomal structures. Nat Cell Biol 12, 747–757 (2010). https://doi.org/10.1038/ncb2078

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