title: Indirect estimation of the area density of Atg8 on the phagophore.
abstract: Atg8 is a ubiquitin-like protein that controls the expansion of the phagophore during autophagosome formation. It is recruited to the phagophore during the expansion stage and released upon the completion of the autophagosome. One possible model explaining the function of Atg8 is that it acts as an adaptor of a coat complex. Here, we tested the coat-adaptor model by estimating the area density of Atg8 molecules on the phagophore. We developed a computational process to simulate the random sectioning of vesicles heterogeneous in size. This method can be applied to estimate the original sizes of intracellular vesicles from sizes of their random sections obtained through transmission electron microscopy. Using this method, we found that the estimated area density of Atg8 is comparable with that of proteins that form the COPII coat.
authors.affiliation: Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-2216, USA.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Xie
authors.forename: Usha
authors.initials: U
authors.lastname: Nair
authors.forename: Jiefei
authors.initials: J
authors.lastname: Geng
authors.forename: Maciej B
authors.initials: MB
authors.lastname: Szefler
authors.forename: Edward D
authors.initials: ED
authors.lastname: Rothman
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Klionsky
mesh_terms: D001343:Autophagy; D000071190:Autophagy-Related Protein 8 Family; D003198:Computer Simulation; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D010588:Phagosomes / Q000378:metabolism* / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: C113757:ATG8 protein, S cerevisiae; D000071190:Autophagy-Related Protein 8 Family; D008869:Microtubule-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins