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Protein / target

Serine/threonine-protein kinase ATR

Encoded byATRQ13535Homo sapiensSwiss-Prot
Clinical-stage
Therapeutic maturity
4
Clinical candidates
27
Clinical trials
Small-molecule tractable
Druggability
Advanced Clinical

Protein at a glance

Biological role

Protein serine/threonine kinase

Strongest disease association

Seckel syndrome 1

Via encoding gene ATR · Genetic evidence · score 0.89

Therapeutic position

Clinically advancing target

Small molecules

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function overview

Serine/threonine protein kinase which activates checkpoint signaling upon genotoxic stresses such as ionizing radiation (IR), ultraviolet light (UV), or DNA replication stalling, thereby acting as a DNA damage sensor.

View complete UniProt function annotation

Serine/threonine protein kinase which activates checkpoint signaling upon genotoxic stresses such as ionizing radiation (IR), ultraviolet light (UV), or DNA replication stalling, thereby acting as a DNA damage sensor (PubMed:10597277, PubMed:10608806, PubMed:10859164, PubMed:11721054, PubMed:12791985, PubMed:12814551, PubMed:14657349, PubMed:14729973, PubMed:14742437, PubMed:15210935, PubMed:15496423, PubMed:16260606, PubMed:21144835, PubMed:21777809, PubMed:23273981, PubMed:25083873, PubMed:27723717, PubMed:27723720, PubMed:30139873, PubMed:33848395, PubMed:37788673, PubMed:37832547, PubMed:9427750, PubMed:9636169). Recognizes the substrate consensus sequence [ST]-Q (PubMed:10597277, PubMed:10608806, PubMed:10859164, PubMed:11721054, PubMed:12791985, PubMed:12814551, PubMed:14657349, PubMed:14729973, PubMed:14742437, PubMed:15210935, PubMed:15496423, PubMed:16260606, PubMed:21144835, PubMed:23273981, PubMed:27723717, PubMed:27723720, PubMed:33848395, PubMed:9427750, PubMed:9636169). Phosphorylates BRCA1, CHEK1, MCM2, RAD17, RBBP8, RPA2, SMC1 and p53/TP53, which collectively inhibit DNA replication and mitosis and promote DNA repair, recombination and apoptosis (PubMed:11114888, PubMed:11418864, PubMed:11865061, PubMed:21777809, PubMed:23273981, PubMed:25083873, PubMed:9925639). Phosphorylates 'Ser-139' of histone variant H2AX at sites of DNA damage, thereby regulating DNA damage response mechanism (PubMed:11673449). Required for FANCD2 ubiquitination (PubMed:15314022). Critical for maintenance of fragile site stability and efficient regulation of centrosome duplication (PubMed:12526805). Acts as a regulator of the S-G2 transition by restricting the activity of CDK1 during S-phase to prevent premature entry into G2 (PubMed:30139873). Acts as a regulator of the nuclear envelope integrity in response to DNA damage and stress (PubMed:25083873, PubMed:37788673, PubMed:37832547). Acts as a mechanical stress sensor at the nuclear envelope: relocalizes to the nuclear envelope in response to mechanical stress and mediates a checkpoint via phosphorylation of CHEK1 (PubMed:25083873). Also promotes nuclear envelope rupture in response to DNA damage by mediating phosphorylation of LMNA at 'Ser-282', leading to lamin disassembly (PubMed:37832547). Involved in the inflammatory response to genome instability and double-stranded DNA breaks: acts by localizing to micronuclei arising from genome instability and catalyzing phosphorylation of LMNA at 'Ser-395', priming LMNA for subsequent phosphorylation by CDK1 and micronuclei envelope rupture (PubMed:37788673). The rupture of micronuclear envelope triggers the cGAS-STING pathway thereby activating the type I interferon response and innate immunity (PubMed:37788673). Positively regulates the restart of stalled replication forks following activation by the KHDC3L-OOEP scaffold complex (By similarity)

Subcellular location

NucleusChromosomeNucleus envelope
Domains and Gene Ontology detail (44)

Domains & features

FATPI3K/PI4K catalyticFATC

Gene Ontology

  • CATR-ATRIP complex
  • Cchromosome
  • Cnuclear envelope
  • Cnucleoplasm
  • Cnucleus
  • CPML body
  • Csite of DNA damage
  • FATP binding
  • FDNA binding
  • Fhistone H2AXS139 kinase activity
  • FMutLalpha complex binding
  • FMutSalpha complex binding

2644 aa · 301 kDa · 3 isoforms

Biological roles

Reactome v97

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Synaptic signallingReactomeCell-cycle regulationGOKinase signallingUniProt · GO
View supporting evidence

Synaptic signalling

  • ·Presynaptic phase of homologous DNA pairing and strand exchange

Cell-cycle regulation

  • ·mitotic G2/M transition checkpoint

Kinase signalling

  • ·Serine/threonine protein kinase which activates checkpoint signaling upon genotoxic stre…
  • ·histone H2AXS139 kinase activity
  • ·protein kinase activity
  • ·protein serine kinase activity
View underlying pathways (11)

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

CHEK1ATMATRIPCHEK2TP53BRCA1TOPBP1RAD9AHUS1CDC7ATR

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Drugs targeting this protein

1

How approved and investigational drugs engage this protein — mechanism and action type, direct vs complex targeting, and how broadly each acts across other targets. A drug-first view (the section above groups the approved ones disease-first); direct binders with few recorded targets are listed first.

ceralasertib
Narrow target profilePhase 3Inhibitor

Serine-protein kinase ATR inhibitor

Direct interaction with this protein · Only this protein recorded as a target

ChEMBL mechanism, action type, target identity and approved indications. Open Targets clinical status.

Translational evidence

Open Targets 26

Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.

Strongest disease associations · via encoding gene ATR

Gene-level evidence surfaced through the gene ATRthat encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.

Seckel syndrome 1
0.91Well supported

Genetic evidence dominant · Open Targets 0.74

Familial cutaneous telangiectasia and oropharyngeal predisposition cancer syndrome
0.78Well supported

Genetic evidence dominant · Open Targets 0.67

Genetic Diseases, Inborn
0.78Well supported

Genetic evidence dominant · Open Targets 0.47

Seckel syndrome
0.72Moderately supported

Genetic literature evidence dominant · Open Targets 0.67

Carcinoma, Non-Small-Cell Lung
0.64Moderately supported

Clinical evidence dominant · Open Targets 0.42

View evidence synthesis (5)
Seckel syndrome 1Well supported
0.91
agreement 0.791.00
Genetic88%Animal model11%Literature1%Genetic literaturedup

Open Targets aggregate 0.74 · 3 independent evidence families · 1 not counted as duplicate

Familial cutaneous telangiectasia and oropharyngeal predisposition cancer syndromeWell supported
0.78
agreement 0.660.90
Genetic100%Genetic literaturedup

Open Targets aggregate 0.67 · 1 independent evidence family · 1 not counted as duplicate

Genetic Diseases, InbornWell supported
0.78
agreement 0.640.92
Genetic99%Literature2%

Open Targets aggregate 0.47 · 2 independent evidence families

Seckel syndromeModerately supported
0.72
agreement 0.590.84
Genetic literature76%Animal model19%Literature6%Geneticdup

Open Targets aggregate 0.67 · 3 independent evidence families · 1 not counted as duplicate

Carcinoma, Non-Small-Cell LungModerately supported
0.64
agreement 0.520.76
Clinical51%Somatic mutation36%Literature14%

Open Targets aggregate 0.42 · 3 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.

Show all associations
Seckel syndrome 10.74
Familial cutaneous telangiectasia and oropharyngeal predisposition cancer syndrome0.67
Seckel syndrome0.67
Microcephalic primordial dwarfism0.51
Genetic Diseases, Inborn0.47
Neurodegenerative Diseases0.46
Carcinoma, Non-Small-Cell Lung0.42
Lung carcinoma0.39
Prostate carcinoma0.38
Skin squamous cell carcinoma0.37

Drug development

4 compounds recorded · 4 in clinical development

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 1 drug that targets this protein in Forefront's canonical graph: these count different sets and are not a subset relation.

View all recorded compounds (4)
BERZOSERTIBPhase 2
ELIMUSERTIBPhase 1 2
CERALASERTIBPhase 3
M4344Phase 1 2

Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.

Tractability

Small moleculesStrong

Advanced Clinical and High-Quality Ligand support this modality.

Protein degradersEmerging

Feasibility evidence (database ubiquitination and half-life data) — no clinical-stage drug of this modality recorded.

View underlying tractability evidence (6)
SM · Advanced ClinicalSM · High-Quality LigandSM · Druggable FamilyPR · Database UbiquitinationPR · Half-life DataPR · Small Molecule Binder

Raw Open Targets tractability assessment buckets, by modality.

Clinical trials

27

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein. Ranked by active status, then clinical phase and recency, and spread across the targeting drugs.

View all trials (23)

ClinicalTrials.gov via the drug-target graph.

What's happening now

1

Recent therapeutic activity around this target — regulatory actions, clinical trials and safety signals for a drug that targets this protein, plus publications where such a drug is a genuine subject. Every item is reached indirectly through the drug, not the protein itself; incidental mentions (a paper that merely measures a drug) and press items are excluded.

  1. New publication2024-02-13
    Biomarker-directed targeted therapy plus durvalumab in advanced non-small-cell lung cancer: a phase 2 umbrella trial.

    Nature medicine · 2024 · 88 citations · Europe PMC · via ceralasertib

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.