Protein / target

Tyrosine-protein kinase BTK

BTKQ06187Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
11
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Non-membrane spanning protein tyrosine kinase activity

Primary system

Immune system

Strongest disease association

X-linked agammaglobulinemia

Genetic evidence · score 0.95

Therapeutic maturity

Clinically validated target

11 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

11 approved · 13 in clinical development

30 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

Non-receptor tyrosine kinase indispensable for B lymphocyte development, differentiation and signaling (PubMed:19290921). Binding of antigen to the B-cell antigen receptor (BCR) triggers signaling that ultimately leads to B-cell activation (PubMed:19290921). After BCR engagement and activation at the plasma membrane, phosphorylates PLCG2 at several sites, igniting the downstream signaling pathway through calcium mobilization, followed by activation of the protein kinase C (PKC) family members (PubMed:11606584). PLCG2 phosphorylation is performed in close cooperation with the adapter protein B-cell linker protein BLNK (PubMed:11606584). BTK acts as a platform to bring together a diverse array of signaling proteins and is implicated in cytokine receptor signaling pathways (PubMed:16517732, PubMed:17932028). Plays an important role in the function of immune cells of innate as well as adaptive immunity, as a component of the Toll-like receptors (TLR) pathway (PubMed:16517732). The TLR pathway acts as a primary surveillance system for the detection of pathogens and are crucial to the activation of host defense (PubMed:16517732). Especially, is a critical molecule in regulating TLR9 activation in splenic B-cells (PubMed:16517732, PubMed:17932028). Within the TLR pathway, induces tyrosine phosphorylation of TIRAP which leads to TIRAP degradation (PubMed:16415872). BTK also plays a critical role in transcription regulation (PubMed:19290921). Induces the activity of NF-kappa-B, which is involved in regulating the expression of hundreds of genes (PubMed:19290921). BTK is involved on the signaling pathway linking TLR8 and TLR9 to NF-kappa-B (PubMed:19290921). Acts as an activator of NLRP3 inflammasome assembly by mediating phosphorylation of NLRP3 (PubMed:34554188). Transiently phosphorylates transcription factor GTF2I on tyrosine residues in response to BCR (PubMed:9012831). GTF2I then translocates to the nucleus to bind regulatory enhancer elements to modulate gene expression (PubMed:9012831). ARID3A and NFAT are other transcriptional target of BTK (PubMed:16738337). BTK is required for the formation of functional ARID3A DNA-binding complexes (PubMed:16738337). There is however no evidence that BTK itself binds directly to DNA (PubMed:16738337). BTK has a dual role in the regulation of apoptosis (PubMed:9751072). Plays a role in STING1-mediated induction of type I interferon (IFN) response by phosphorylating DDX41 (PubMed:25704810)

Subcellular location

CytoplasmCell membraneNucleusMembrane raft
Domains and Gene Ontology detail (58)

Domains & features

PHSH3SH2Protein kinase

Gene Ontology

  • Ccytoplasm
  • Ccytoplasmic vesicle
  • Ccytosol
  • Cmembrane raft
  • Cnucleus
  • Cperinuclear region of cytoplasm
  • Cplasma membrane
  • FATP binding
  • Fidentical protein binding
  • Fnon-membrane spanning protein tyrosine kinase activity
  • Fphosphatidylinositol-3,4,5-trisphosphate binding
  • Fphospholipase activator activity

659 aa · 76 kDa · 2 isoforms

Biological roles

Reactome v97

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

Immune signallingUniProt · GO · ReactomeKinase signallingUniProt · GOTranscriptional regulationUniProt · GOApoptosis & cell deathGO
View supporting evidence

Immune signalling

  • ·Non-receptor tyrosine kinase indispensable for B lymphocyte development, differentiation…
  • ·adaptive immune response
  • ·B cell activation
  • ·B cell receptor signaling pathway

Kinase signalling

  • ·Non-receptor tyrosine kinase indispensable for B lymphocyte development, differentiation…
  • ·non-membrane spanning protein tyrosine kinase activity
  • ·protein tyrosine kinase activity
  • ·peptidyl-tyrosine phosphorylation

Transcriptional regulation

  • ·Non-receptor tyrosine kinase indispensable for B lymphocyte development, differentiation…
  • ·DNA-templated transcription

Apoptosis & cell death

  • ·regulation of B cell apoptotic process
View underlying pathways (14)

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.

LCP2SYKPLCG2BLNKLYNVAV1MYD88GRB2GTF2IPIK3CDBTK

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.

ibrutinib
Narrow target profileApprovedInhibitor

Tyrosine-protein kinase BTK inhibitor

Appears in clinical studies involving macroglobulinemia, mantle cell lymphoma, B-cell chronic lymphocytic leukemia, B-cell chronic lymphocytic leukemia

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.

X-linked agammaglobulinemia0.95

Genetic · overall 0.85

isolated growth hormone deficiency type III0.94

Genetic · overall 0.73

Non-acquired isolated growth hormone deficiency0.94

Genetic · overall 0.73

Bruton-type agammaglobulinemia0.86

Genetic literature · overall 0.70

isolated agammaglobulinemia0.82

Genetic · overall 0.69

Highest-confidence therapeutic associations

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

B-cell chronic lymphocytic leukemia0.99

Clinical · overall 0.72

mantle cell lymphoma0.98

Clinical · overall 0.69

alopecia areata0.92

Clinical · overall 0.56

Waldenstrom macroglobulinemia0.91

Clinical · overall 0.56

neoplasm0.91

Clinical · overall 0.59

Show all associations
X-linked agammaglobulinemia0.85
isolated growth hormone deficiency type III0.73
Non-acquired isolated growth hormone deficiency0.73
B-cell chronic lymphocytic leukemia0.72
Bruton-type agammaglobulinemia0.70
mantle cell lymphoma0.69
isolated agammaglobulinemia0.69
neoplasm0.59
Waldenstrom macroglobulinemia0.56
alopecia areata0.56

Open Targets ranks 928 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 · 24 total

VECABRUTINIBPhase 1 2

B-cell non-Hodgkin lymphoma · mantle cell lymphoma · follicular lymphoma

TOLEBRUTINIBPreapproval

chronic progressive multiple sclerosis · multiple sclerosis · myasthenia gravis

PIRTOBRUTINIBApproval

mantle cell lymphoma · non-Hodgkin lymphoma · neoplasm

ACALABRUTINIBApproval

B-cell chronic lymphocytic leukemia · B-cell chronic lymphocytic leukemia · childhood leukemia

ELSUBRUTINIBPhase 2

rheumatoid arthritis · systemic lupus erythematosus

ZANUBRUTINIBApproval

mantle cell lymphoma · B-cell chronic lymphocytic leukemia · lymphoplasmacytic lymphoma

SPEBRUTINIBPhase 2

B-cell chronic lymphocytic leukemia · rheumatoid arthritis · non-Hodgkin lymphoma

ABIVERTINIBPhase 3

non-small cell lung carcinoma · non-small cell lung carcinoma · prostate cancer

ORELABRUTINIBApproval

neoplasm · B-cell chronic lymphocytic leukemia · B-cell chronic lymphocytic leukemia

MSC-2364447Phase 1

systemic lupus erythematosus

Tractability

SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · High-Quality PocketSM · Druggable FamilyAB · UniProt loc high confAB · GO CC high confAB · Human Protein Atlas locPR · Phase 1 ClinicalPR · LiteraturePR · Database UbiquitinationPR · Half-life Data

Safety liabilities

regulation of catalytic activity

Clinical trials

30

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 (24)

COMPLETED · via ibrutinib · NCT03149315

UNKNOWN · via ibrutinib · NCT04025593

ACTIVE_NOT_RECRUITING · via ibrutinib · NCT02007044

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.

X-linked agammaglobulinemiaWell supported
0.96
agreement 0.841.00
Genetic81%Animal model15%Literature4%Genetic literaturedup

Open Targets aggregate 0.85 · 3 independent evidence families · 1 not counted as duplicate

isolated growth hormone deficiency type IIIWell supported
0.95
agreement 0.831.00
Genetic87%Animal model13%Genetic literaturedup

Open Targets aggregate 0.73 · 2 independent evidence families · 1 not counted as duplicate

Non-acquired isolated growth hormone deficiencyWell supported
0.95
agreement 0.831.00
Genetic87%Animal model13%Genetic literaturedup

Open Targets aggregate 0.73 · 2 independent evidence families · 1 not counted as duplicate

B-cell chronic lymphocytic leukemiaWell supported
0.90
agreement 0.791.00
Clinical49%Somatic mutation26%Pathway16%Literature10%

Open Targets aggregate 0.72 · 4 independent evidence families

mantle cell lymphomaWell supported
0.88
agreement 0.770.98
Clinical52%Somatic mutation21%Pathway17%Literature10%

Open Targets aggregate 0.69 · 4 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

4

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 publication2019-08-01
    Ibrutinib-Rituximab or Chemoimmunotherapy for Chronic Lymphocytic Leukemia.

    The New England journal of medicine · 2019 · 563 citations · Europe PMC · via ibrutinib

  2. New publication2018-06-05
    A head-to-head Phase III study comparing zanubrutinib versus ibrutinib in patients with Waldenström macroglobulinemia.

    Future oncology (London, England) · 2018 · 28 citations · Europe PMC · via ibrutinib

  3. Safety communication2017-08-15

    Drug Safety Update: Ibrutinib (Imbruvica▼): reports of ventricular tachyarrhythmia; risk of hepatitis B reactivation and of opportunistic infections

    mhra · safety · mhra · via ibrutinib

  4. Regulatory approval2014-10-21

    Approval: Imbruvica (EMA)

    ema · regulatory · ema · via ibrutinib

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.