Abstract
ATR (ataxia telangiectasia-mutated and Rad3-related) protein kinase and ATRIP (ATR-interacting protein) form a complex and play a critical role in response to replication stress and DNA damage. Here, we determined the cryo-electron microscopy (EM) structure of the human ATR-ATRIP complex at 4.7 Å resolution and built an atomic model of the C-terminal catalytic core of ATR (residues 1 521-2 644) at 3.9 Å resolution. The complex adopts a hollow "heart" shape, consisting of two ATR monomers in distinct conformations. The EM map for ATRIP reveals 14 HEAT repeats in an extended "S" shape. The conformational flexibility of ATR allows ATRIP to properly lock the N-termini of the two ATR monomers to favor ATR-ATRIP complex formation and functional diversity. The isolated "head-head" and "tail-tail" each adopts a pseudo 2-fold symmetry. The catalytic pockets face outward and substrate access is not restricted by inhibitory elements. Our studies provide a structural basis for understanding the assembly of the ATR-ATRIP complex and a framework for characterizing ATR-mediated DNA repair pathways.
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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Ataxia Telangiectasia Mutated Proteins / antagonists & inhibitors
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Ataxia Telangiectasia Mutated Proteins / chemistry*
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Ataxia Telangiectasia Mutated Proteins / genetics
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Ataxia Telangiectasia Mutated Proteins / metabolism*
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Carrier Proteins / metabolism
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Chromatography, Affinity
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Chromatography, Gel
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Cryoelectron Microscopy
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DNA Damage
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DNA-Binding Proteins / chemistry*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Humans
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Isoxazoles / metabolism
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Mutation
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Nuclear Proteins / metabolism
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Phosphorylation
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Protein Binding
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Protein Conformation, alpha-Helical
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Protein Folding
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Protein Kinases / metabolism
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Protein Multimerization
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Pyrazines / metabolism
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Signal Transduction
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TOR Serine-Threonine Kinases / chemistry
Substances
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ATRIP protein, human
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Adaptor Proteins, Signal Transducing
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Carrier Proteins
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DNA-Binding Proteins
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Isoxazoles
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Nuclear Proteins
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Pyrazines
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TOPBP1 protein, human
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Protein Kinases
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MTOR protein, human
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ATR protein, human
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Ataxia Telangiectasia Mutated Proteins
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TOR Serine-Threonine Kinases
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berzosertib