Abstract
The ULK1 complex, consisting of the ULK1 protein kinase itself, FIP200, Atg13, and Atg101, controls the initiation of autophagy in animals. We determined the structure of the complex of the human Atg13 HORMA (Hop1, Rev7, Mad2) domain in complex with the full-length HORMA domain-only protein Atg101. The two HORMA domains assemble with an architecture conserved in the Mad2 conformational heterodimer and the S. pombe Atg13-Atg101 HORMA complex. The WF finger motif that is essential for function in human Atg101 is sequestered in a hydrophobic pocket, suggesting that the exposure of this motif is regulated. Benzamidine molecules from the crystallization solution mark two hydrophobic pockets that are conserved in, and unique to, animals, and are suggestive of sites that could interact with other proteins. These features suggest that the activity of the animal Atg13-Atg101 subcomplex is regulated and that it is an interaction hub for multiple partners.
Keywords:
Atg1; X-ray crystallography; autophagy; hydrogen-deuterium exchange; protein structure.
Copyright © 2015 Elsevier Ltd. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing / chemistry*
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / metabolism
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Amino Acid Sequence
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Animals
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Autophagy / genetics*
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Autophagy-Related Protein-1 Homolog
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Autophagy-Related Proteins
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Benzamidines / chemistry
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Binding Sites
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Crystallography, X-Ray
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Gene Expression
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Humans
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Hydrophobic and Hydrophilic Interactions
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Intracellular Signaling Peptides and Proteins / chemistry*
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / metabolism
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Mad2 Proteins / chemistry*
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Mad2 Proteins / genetics
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Mad2 Proteins / metabolism
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Models, Molecular
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Molecular Sequence Data
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Mutation
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Protein Binding
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Protein Multimerization
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Protein Serine-Threonine Kinases / chemistry*
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Protein Structure, Secondary
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Protein Structure, Tertiary
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism
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Sequence Alignment
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Sf9 Cells
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Spodoptera
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Vesicular Transport Proteins / chemistry*
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Vesicular Transport Proteins / genetics
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Vesicular Transport Proteins / metabolism
Substances
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ATG13 protein, human
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Adaptor Proteins, Signal Transducing
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ATG101 protein, human
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Autophagy-Related Proteins
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Benzamidines
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Intracellular Signaling Peptides and Proteins
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MAD2L1 protein, human
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Mad2 Proteins
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Recombinant Proteins
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Vesicular Transport Proteins
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Autophagy-Related Protein-1 Homolog
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Protein Serine-Threonine Kinases
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ULK1 protein, human
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benzamidine