title: Membrane dynamics in autophagosome biogenesis.
abstract: Bilayered phospholipid membranes are vital to the organization of the living cell. Based on fundamental principles of polarity, membranes create borders allowing defined spaces to be encapsulated. This compartmentalization is a prerequisite for the complex functional design of the eukaryotic cell, yielding localities that can differ in composition and operation. During macroautophagy, cytoplasmic components become enclosed by a growing double bilayered membrane, which upon closure creates a separate compartment, the autophagosome. The autophagosome is then primed for fusion with endosomal and lysosomal compartments, leading to degradation of the captured material. A large number of proteins have been found to be essential for autophagy, but little is known about the specific lipids that constitute the autophagic membranes and the membrane modeling events that are responsible for regulation of autophagosome shape and size. In this Commentary, we review the recent progress in our understanding of the membrane shaping and remodeling events that are required at different steps of the autophagy pathway. This article is part of a Focus on Autophagosome biogenesis. For further reading, please see related articles: 'ERES: sites for autophagosome biogenesis and maturation?' by Jana Sanchez-Wandelmer et al. (J. Cell Sci. 128, 185-192) and 'WIPI proteins: essential PtdIns3P effectors at the nascent autophagosome' by Tassula Proikas-Cezanne et al. (J. Cell Sci. 128, 207-217).
authors.affiliation: Department of Medical Biochemistry and Biophysics, University of Umeå, SE-901 87 Umeå, Sweden sven.carlsson@medchem.umu.se anne.simonsen@medisin.uio.no.
authors.forename: Sven R
authors.initials: SR
authors.lastname: Carlsson
authors.affiliation: Institute of Basic Medical Sciences, University of Oslo, NO-0317 Oslo, Norway sven.carlsson@medchem.umu.se anne.simonsen@medisin.uio.no.
authors.forename: Anne
authors.initials: A
authors.lastname: Simonsen
mesh_terms: D001343:Autophagy / Q000235:genetics*; D000071189:Autophagy-Related Protein-1 Homolog; D002450:Cell Communication / Q000235:genetics; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008055:Lipids / Q000235:genetics; D008247:Lysosomes / Q000378:metabolism; D010588:Phagosomes / Q000235:genetics* / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008055:Lipids; D018129:Phosphatidylinositol Phosphates; C055525:phosphatidylinositol 3-phosphate; D000071189:Autophagy-Related Protein-1 Homolog; D017346:Protein Serine-Threonine Kinases; C484754:ULK1 protein, human
keywords: Atg; Autophagosome; Phagophore; PtdIns3P