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Elife. 2014 Dec 9;3. doi: 10.7554/eLife.05115.

Architecture and dynamics of the autophagic phosphatidylinositol 3-kinase complex.

Author information

1
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.
2
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States.

Abstract

The class III phosphatidylinositol 3-kinase complex I (PI3KC3-C1) that functions in early autophagy consists of the lipid kinase VPS34, the scaffolding protein VPS15, the tumor suppressor BECN1, and the autophagy-specific subunit ATG14. The structure of the ATG14-containing PI3KC3-C1 was determined by single-particle EM, revealing a V-shaped architecture. All of the ordered domains of VPS34, VPS15, and BECN1 were mapped by MBP tagging. The dynamics of the complex were defined using hydrogen-deuterium exchange, revealing a novel 20-residue ordered region C-terminal to the VPS34 C2 domain. VPS15 organizes the complex and serves as a bridge between VPS34 and the ATG14:BECN1 subcomplex. Dynamic transitions occur in which the lipid kinase domain is ejected from the complex and VPS15 pivots at the base of the V. The N-terminus of BECN1, the target for signaling inputs, resides near the pivot point. These observations provide a framework for understanding the allosteric regulation of lipid kinase activity.

KEYWORDS:

autophagy; biophysics; human; hydrogen–deuterium exchange; lipid kinase; protein kinase; structural biology; three dimensional electron microscopy

PMID:
25490155
PMCID:
PMC4281882
DOI:
10.7554/eLife.05115
[Indexed for MEDLINE]
Free PMC Article

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