CapZ regulates autophagosomal membrane shaping by promoting actin assembly inside the isolation membrane

Mi, N; Chen, Y; Wang, S; Chen, M; Zhao, M; Yang, G; Ma, M; Su, Q; Luo, S; Shi, J; Xu, J; Guo, Q; Gao, N; Sun, Y; Chen, Z; Yu, L

CapZ regulates autophagosomal membrane shaping by promoting actin assembly inside the isolation membrane

Mi, N Chen, Y Wang, S Chen, M Zhao, M Yang, G Ma, M Su, Q

Luo, S Shi, J Xu, J Guo, Q Gao, N Sun, Y Chen, Z Yu, L

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Publication Type:: Journal Article
Citation:: Nature Cell Biology, 2015, 17 (9), pp. 1112 - 1123
Issue Date:: 2015-09-01

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Field	Value	Language
dc.contributor.author	Mi, N	en_US
dc.contributor.author	Chen, Y	en_US
dc.contributor.author	Wang, S	en_US
dc.contributor.author	Chen, M	en_US
dc.contributor.author	Zhao, M	en_US
dc.contributor.author	Yang, G	en_US
dc.contributor.author	Ma, M	en_US
dc.contributor.author	Su, Q https://orcid.org/0000-0001-7364-3945	en_US
dc.contributor.author	Luo, S	en_US
dc.contributor.author	Shi, J	en_US
dc.contributor.author	Xu, J	en_US
dc.contributor.author	Guo, Q	en_US
dc.contributor.author	Gao, N	en_US
dc.contributor.author	Sun, Y	en_US
dc.contributor.author	Chen, Z	en_US
dc.contributor.author	Yu, L	en_US
dc.date.available	2015-07-01	en_US
dc.date.issued	2015-09-01	en_US
dc.identifier.citation	Nature Cell Biology, 2015, 17 (9), pp. 1112 - 1123	en_US
dc.identifier.issn	1465-7392	en_US
dc.identifier.uri	http://hdl.handle.net/10453/119450
dc.description.abstract	© 2015 Macmillan Publishers Limited. A fundamental question regarding autophagosome formation is how the shape of the double-membrane autophagosomal vesicle is generated. Here we show that in mammalian cells assembly of an actin scaffold inside the isolation membrane (the autophagosomal precursor) is essential for autophagosomal membrane shaping. Actin filaments are depolymerized shortly after starvation and actin is assembled into a network within the isolation membrane. When formation of actin puncta is disrupted by an actin polymerization inhibitor or by knocking down the actin-capping protein CapZβ, isolation membranes and omegasomes collapse into mixed-membrane bundles. Formation of actin puncta is PtdIns(3)P dependent, and inhibition of PtdIns(3)P formation by treating cells with the PI(3)K inhibitor 3-MA, or by knocking down Beclin-1, abolishes the formation of actin puncta. Binding of CapZ to PtdIns(3)P, which is enriched in omegasomes, stimulates actin polymerization. Our findings illuminate the mechanism underlying autophagosomal membrane shaping and provide key insights into how autophagosomes are formed.	en_US
dc.relation.ispartof	Nature Cell Biology	en_US
dc.relation.isbasedon	10.1038/ncb3215	en_US
dc.subject.classification	Developmental Biology	en_US
dc.subject.mesh	Cells, Cultured	en_US
dc.subject.mesh	Intracellular Membranes	en_US
dc.subject.mesh	Phagosomes	en_US
dc.subject.mesh	Animals	en_US
dc.subject.mesh	Rats	en_US
dc.subject.mesh	Phosphatidylinositol Phosphates	en_US
dc.subject.mesh	Protein Binding	en_US
dc.subject.mesh	Protein Transport	en_US
dc.subject.mesh	Autophagy	en_US
dc.subject.mesh	CapZ Actin Capping Protein	en_US
dc.subject.mesh	Protein Multimerization	en_US
dc.subject.mesh	Actin Cytoskeleton	en_US
dc.title	CapZ regulates autophagosomal membrane shaping by promoting actin assembly inside the isolation membrane	en_US
dc.type	Journal Article
utslib.citation.volume	9	en_US
utslib.citation.volume	17	en_US
utslib.for	0601 Biochemistry and Cell Biology	en_US
utslib.for	06 Biological Sciences	en_US
utslib.for	11 Medical and Health Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
utslib.copyright.status	closed_access
pubs.issue	9	en_US
pubs.publication-status	Published	en_US
pubs.volume	17	en_US

Abstract:

© 2015 Macmillan Publishers Limited. A fundamental question regarding autophagosome formation is how the shape of the double-membrane autophagosomal vesicle is generated. Here we show that in mammalian cells assembly of an actin scaffold inside the isolation membrane (the autophagosomal precursor) is essential for autophagosomal membrane shaping. Actin filaments are depolymerized shortly after starvation and actin is assembled into a network within the isolation membrane. When formation of actin puncta is disrupted by an actin polymerization inhibitor or by knocking down the actin-capping protein CapZβ, isolation membranes and omegasomes collapse into mixed-membrane bundles. Formation of actin puncta is PtdIns(3)P dependent, and inhibition of PtdIns(3)P formation by treating cells with the PI(3)K inhibitor 3-MA, or by knocking down Beclin-1, abolishes the formation of actin puncta. Binding of CapZ to PtdIns(3)P, which is enriched in omegasomes, stimulates actin polymerization. Our findings illuminate the mechanism underlying autophagosomal membrane shaping and provide key insights into how autophagosomes are formed.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/119450