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Protein / target

Proprotein convertase subtilisin/kexin type 9

Encoded byPCSK9Q8NBP7Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
4
Approved medicines
Open Targets target-level
View by indication →
30
Clinical trials
Small-molecule tractable
Druggability
Structure with Ligand

Protein at a glance

Biological role

Very-low-density lipoprotein particle receptor binding

Strongest disease association

Hypercholesterolemia, autosomal dominant, 3

Via encoding gene PCSK9 · Genetic evidence · score 0.94

Therapeutic position

Established drug target

Antibodies

Research activity

Emerging research

15 papers · latest 2026

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

Crucial player in the regulation of plasma cholesterol homeostasis.

View complete UniProt function annotation

Crucial player in the regulation of plasma cholesterol homeostasis. Binds to low-density lipid receptor family members: low density lipoprotein receptor (LDLR), very low density lipoprotein receptor (VLDLR), apolipoprotein E receptor (LRP1/APOER) and apolipoprotein receptor 2 (LRP8/APOER2), and promotes their degradation in intracellular acidic compartments (PubMed:18039658). Acts via a non-proteolytic mechanism to enhance the degradation of the hepatic LDLR through a clathrin LDLRAP1/ARH-mediated pathway. May prevent the recycling of LDLR from endosomes to the cell surface or direct it to lysosomes for degradation. Can induce ubiquitination of LDLR leading to its subsequent degradation (PubMed:17461796, PubMed:18197702, PubMed:18799458, PubMed:22074827). Inhibits intracellular degradation of APOB via the autophagosome/lysosome pathway in a LDLR-independent manner. Involved in the disposal of non-acetylated intermediates of BACE1 in the early secretory pathway (PubMed:18660751). Inhibits epithelial Na(+) channel (ENaC)-mediated Na(+) absorption by reducing ENaC surface expression primarily by increasing its proteasomal degradation. Regulates neuronal apoptosis via modulation of LRP8/APOER2 levels and related anti-apoptotic signaling pathways

Subcellular location

CytoplasmSecretedEndosomeLysosomeCell surfaceEndoplasmic reticulumGolgi apparatus
Domains and Gene Ontology detail (53)

Domains & features

Inhibitor I9Peptidase S8

Gene Ontology

  • Ccell surface
  • CCOPII-coated ER to Golgi transport vesicle
  • Ccytoplasm
  • Cearly endosome
  • Cendolysosome membrane
  • Cendoplasmic reticulum
  • Cendoplasmic reticulum lumen
  • Cextracellular region
  • Cextracellular space
  • Cextrinsic component of external side of plasma membrane
  • CGolgi apparatus
  • Clate endosome

692 aa · 74 kDa · 2 isoforms

Biological roles

Reactome v97

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

Lipid & lipoprotein metabolismUniProt · GOApoptosis & cell deathGOProteolysisGO
View supporting evidence

Lipid & lipoprotein metabolism

  • ·Crucial player in the regulation of plasma cholesterol homeostasis. Binds to low-density…
  • ·apolipoprotein binding
  • ·apolipoprotein receptor binding
  • ·low-density lipoprotein particle binding

Apoptosis & cell death

  • ·apoptotic process
  • ·positive regulation of neuron apoptotic process
  • ·regulation of neuron apoptotic process

Proteolysis

  • ·endopeptidase activity
  • ·serine-type endopeptidase activity
View underlying pathways (4)

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.

LDLRAPOBVLDLRHMGCRIGLL5IGKV1D…IGKV1-…IGHV3-…GOLPH3PCSK5PCSK9

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.

Approved medicines with mapped indications

2 medicines · 8 areas

Approved therapies targeting this protein, grouped by what they are approved to treat — the disease-first view of the medicines below. Relationships come from the canonical approved-indication graph (ChEMBL phase-4), the same source as the drug cards.

Coronary Artery Disease2 medicines
Dyslipidemias2 medicines
Hyperlipoproteinemia Type II2 medicines
Atherosclerosis1 medicine
Hypercholesterolemia1 medicine
Myocardial Infarction1 medicine
Stroke1 medicine
Broader indication categories (1)
Cardiovascular Diseases2 medicines

Broad umbrella indications (e.g. “Neoplasms”). Shown here because every medicine also appears under a more specific disease above — kept for completeness, de-emphasised for clarity.

4 medicines meet Open Targets' target-level approved-medicine definition; the 2 shown here are those on this page with a canonical approved disease indication in the graph. Approved indications from ChEMBL (phase-4), via the canonical drug→disease graph.

Drugs targeting this protein

2

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.

evolocumab
Narrow target profileApprovedInhibitor

Subtilisin/kexin type 9 inhibitor

Indicated for Coronary Artery Disease, Dyslipidemias, Hypercholesterolemia, Hyperlipoproteinemia Type II

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

alirocumab
Narrow target profileApprovedInhibitor

Subtilisin/kexin type 9 inhibitor

Indicated for Atherosclerosis, Coronary Artery Disease, Dyslipidemias, Hyperlipoproteinemia Type II

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 PCSK9

Gene-level evidence surfaced through the gene PCSK9that 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.

Coronary Artery Disease
0.98Well supported

Genetic evidence dominant · Open Targets 0.72

Familial hypercholesterolemia
0.97Well supported

Genetic evidence dominant · Open Targets 0.85

Cardiovascular Diseases
0.97Well supported

Genetic evidence dominant · Open Targets 0.72

Hyperlipidemias
0.95Well supported

Genetic evidence dominant · Open Targets 0.66

Hypercholesterolemia, autosomal dominant, 3
0.95Well supported

Genetic evidence dominant · Open Targets 0.82

View evidence synthesis (5)
Coronary Artery DiseaseWell supported
0.98
agreement 0.871.00
Genetic52%Clinical40%Literature8%

Open Targets aggregate 0.72 · 3 independent evidence families

Familial hypercholesterolemiaWell supported
0.97
agreement 0.881.00
Genetic45%Clinical38%Animal model11%Literature6%Genetic literaturedup

Open Targets aggregate 0.85 · 4 independent evidence families · 1 not counted as duplicate

Cardiovascular DiseasesWell supported
0.97
agreement 0.861.00
Genetic53%Clinical43%Literature4%

Open Targets aggregate 0.72 · 3 independent evidence families

HyperlipidemiasWell supported
0.95
agreement 0.851.00
Genetic61%Clinical33%Literature6%

Open Targets aggregate 0.66 · 3 independent evidence families

Hypercholesterolemia, autosomal dominant, 3Well supported
0.95
agreement 0.851.00
Genetic80%Animal model17%Somatic mutation2%Literature1%Genetic literaturedup

Open Targets aggregate 0.82 · 4 independent evidence families · 1 not counted as duplicate

This ranking differs from Open Targets' own: re-weighting moves genetically-evidenced diseases above more heavily co-mentioned ones. 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
Familial hypercholesterolemia0.85
Hypercholesterolemia, autosomal dominant, 30.82
Cardiovascular Diseases0.72
Coronary Artery Disease0.72
Metabolic Diseases0.71
Hyperlipidemias0.66
Myocardial Infarction0.65
Homozygous familial hypercholesterolemia0.65
Disorder of lipid metabolism0.65

Drug development

10 compounds recorded · 4 approved · 6 in clinical development

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 2 drugs that target this protein in Forefront's canonical graph (2 with a mapped approved indication, shown above): these count different sets and are not a subset relation.

View all recorded compounds (10)
BOCOCIZUMABPhase 3
LERODALCIBEPPhase 3
ONGERICIMABPhase 3
TAFOLECIMABPhase 3
INCLISIRAN SODIUMApproval
ALIROCUMABApproval
INCLISIRANApproval
RALPANCIZUMABPhase 1
EVOLOCUMABApproval
FROVOCIMABPhase 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 moleculesEmerging

Feasibility evidence (structure with ligand and high-quality ligand) — no clinical-stage drug of this modality recorded.

AntibodiesStrong

Approved Drug and GO CC high conf support this modality.

Protein degradersEmerging

Feasibility evidence (database ubiquitination and small molecule binder) — no clinical-stage drug of this modality recorded.

Other modalitiesStrong

Advanced Clinical support this modality.

View underlying tractability evidence (10)
SM · Structure with LigandSM · High-Quality LigandSM · High-Quality PocketAB · Approved DrugAB · GO CC high confAB · UniProt loc med confAB · UniProt SigP or TMHMMPR · Database UbiquitinationPR · Small Molecule BinderOC · Advanced Clinical

Raw Open Targets tractability assessment buckets, by modality.

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. Ranked by active status, then clinical phase and recency, and spread across the targeting drugs.

View all trials (26)

TERMINATED · via evolocumab · NCT04573777

WITHDRAWN · via alirocumab · NCT03750760

ClinicalTrials.gov via the drug-target graph.

What's happening now

12

Recent therapeutic activity around this target — regulatory actions, clinical trials and safety signals for 2 drugs that target 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. Label change2026-07-15

    Label change: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  2. Label change2025-08-21

    Label change: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  3. Label change2024-11-20

    Label change: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  4. Label change2024-08-20

    Label change: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  5. New publication2022-08-29
    Long-Term Evolocumab in Patients With Established Atherosclerotic Cardiovascular Disease.

    Circulation · 2022 · 268 citations · Europe PMC · via evolocumab

  6. Label change2022-08-16

    Label change: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  7. Indication expanded2021-09-24

    Indication expansion: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  8. Regulatory approval2021-02-26

    Approval: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  9. New publication2018-11-07
    Alirocumab and Cardiovascular Outcomes after Acute Coronary Syndrome.

    The New England journal of medicine · 2018 · 2,537 citations · Europe PMC · via alirocumab

  10. Regulatory approval2015-08-27

    Approval: EVOLOCUMAB (BLA125522)

    fda · regulatory · fda · via evolocumab

  11. New publication2015-03-15
    Efficacy and safety of alirocumab in reducing lipids and cardiovascular events.

    The New England journal of medicine · 2015 · 1,506 citations · Europe PMC · via alirocumab

  12. New publication2015-03-15
    Efficacy and safety of evolocumab in reducing lipids and cardiovascular events.

    The New England journal of medicine · 2015 · 1,158 citations · Europe PMC · via evolocumab

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.

Research activity

15 papers · to 2026

Papers linked directly to this protein. This is the protein's own literature — descriptor-derived papers are kept separate below.

Most cited

Recent

Europe PMC papers linked directly to this protein.