Protein / target

Serine/threonine-protein kinase ATR

ATRQ13535Homo 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 activity

Primary system

Immune system

Strongest disease association

Seckel syndrome 1

Genetic evidence · score 0.89

Therapeutic maturity

Clinical-stage target

4 candidates in clinical development

Druggability

Small molecule

Open Targets tractability · Advanced Clinical

Clinical development

4 in clinical development

27 linked trials

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

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.

Kinase signallingUniProt · GO · ReactomeSynaptic signallingReactomeImmune signallingUniProtMetabolic enzyme activityGOTranscriptional regulationReactome
View supporting evidence

Kinase signalling

  • ·Serine/threonine protein kinase which activates checkpoint signaling upon genotoxic stre…
  • ·histone H2AXS139 kinase activity
  • ·protein kinase activity
  • ·protein serine kinase activity

Synaptic signalling

  • ·Presynaptic phase of homologous DNA pairing and strand exchange

Immune signalling

  • ·Serine/threonine protein kinase which activates checkpoint signaling upon genotoxic stre…

Metabolic enzyme activity

  • ·nucleobase-containing compound metabolic process

Transcriptional regulation

  • ·TP53 Regulates Transcription of DNA Repair Genes
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

Whether each drug engages this protein directly or through a complex, and how many other targets are recorded for it. Direct binders with few recorded targets are listed first.

ceralasertib
Narrow target profilePhase 3Inhibitor

Serine-protein kinase ATR inhibitor

Appears in clinical studies involving non-small cell lung carcinoma, small cell lung carcinoma, small cell lung carcinoma, ovarian cancer

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

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

Translational evidence

Open Targets 26

Why this target matters therapeutically — disease associations, drugs in development, tractability and safety, from Open Targets.

Strongest genetic associations

Human genetic evidence — the most direct causal link between this target and a disease.

Seckel syndrome 10.89

Genetic · overall 0.74

Seckel syndrome0.81

Genetic literature · overall 0.67

familial cutaneous telangiectasia and oropharyngeal predisposition cancer syndrome0.78

Genetic · overall 0.67

hereditary disease0.78

Genetic · overall 0.47

microcephalic primordial dwarfism0.61

Genetic literature · overall 0.51

Highest-confidence therapeutic associations

Diseases where a drug acting on this target has already reached clinical development.

non-small cell lung carcinoma0.56

Clinical · overall 0.42

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

neurodegenerative disease0.46

Pathway

lung carcinoma0.39

Somatic mutation

prostate carcinoma0.38

Somatic mutation

skin squamous cell carcinoma0.37

Somatic mutation

Show all associations
Seckel syndrome 10.74
familial cutaneous telangiectasia and oropharyngeal predisposition cancer syndrome0.67
Seckel syndrome0.67
microcephalic primordial dwarfism0.51
hereditary disease0.47
neurodegenerative disease0.46
non-small cell lung carcinoma0.42
lung carcinoma0.39
prostate carcinoma0.38
skin squamous cell carcinoma0.37

Open Targets ranks 1,360 associations for this target and we store the top 10 by aggregated score. The long tail is largely literature co-mention and RNA-expression evidence, not evidence that this target drives those diseases.

Known drugs · 4 total

BERZOSERTIBPhase 2

primary peritoneal carcinoma · fallopian tube cancer · ovarian cancer

ELIMUSERTIBPhase 1 2

Ewing sarcoma · alveolar rhabdomyosarcoma · lymphoma

CERALASERTIBPhase 3

non-small cell lung carcinoma · small cell lung carcinoma · small cell lung carcinoma

M4344Phase 1 2

breast cancer · neoplasm · ovarian cancer

Tractability

SM · Advanced ClinicalSM · High-Quality LigandSM · Druggable FamilyPR · Database UbiquitinationPR · Half-life DataPR · Small Molecule Binder

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.

Show remaining trials (21)

ClinicalTrials.gov via the drug-target graph.

Forefront confidence

Synthesis

Our own weighting of the evidence behind each disease association. Human genetics and clinical evidence count for most; literature co-mention counts for little, because two entities sharing an abstract is not evidence that one drives the other.

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

hereditary diseaseWell 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

non-small cell lung carcinomaModerately 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 underlying per-type scores are shown above so the calculation can be checked.

What's happening now

2

Recent activity around this target, drawn from one canonical event stream. Every item is reached through a drug that targets this protein, so each event is news about that drug rather than about the protein directly.

  1. New publication2024-02-24
    The ATR inhibitor ceralasertib potentiates cancer checkpoint immunotherapy by regulating the tumor microenvironment.

    Nature communications · 2024 · 38 citations · Europe PMC · via ceralasertib

  2. 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.