Protein / target

Myosin light chain 3

MYL3P08590Homo sapiensSwiss-Prot
UniProt: P08590Ensembl: ENSG00000160808HGNC: HGNC:7584NCBI Gene: 4634
Clinically validated
Therapeutic maturity
2
Approved medicines
10
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Structural constituent of muscle

Primary system

Musculoskeletal system

Strongest disease association

hypertrophic cardiomyopathy

Genetic evidence · score 0.88

Therapeutic maturity

Clinically validated target

2 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

2 approved · 1 in clinical development

10 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

Regulatory light chain of myosin. Does not bind calcium

Domains and Gene Ontology detail (20)

Domains & features

EF-hand 1EF-hand 2EF-hand 3

Gene Ontology

  • CA band
  • Ccytosol
  • CI band
  • Cmuscle myosin complex
  • Cmyosin II complex
  • Csarcomere
  • Factin monomer binding
  • Fcalcium ion binding
  • Fcytoskeletal motor activity
  • Fmyosin II heavy chain binding
  • Fstructural constituent of muscle
  • Pcardiac muscle contraction

195 aa · 22 kDa

Biological roles

Reactome v97

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

Muscle contractionUniProt · GO · Reactome
View supporting evidence

Muscle contraction

  • ·Regulatory light chain of myosin. Does not bind calcium
  • ·muscle myosin complex
  • ·myosin II complex
  • ·sarcomere
View underlying pathways (1)
Striated Muscle Contraction

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.

MYL2MYH7MYH6ACTC1MYLK2MYBPC3MYL4TNNI3TNNT2TPM1MYL3

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.

omecamtiv mecarbil
ApprovedActivator

Cardiac myosin activator

Appears in clinical studies involving cardiovascular disorder, heart failure, heart failure, Stroke

Acts on a complex — shared with MYH7, MYH6, MYH7B +3 more · 1 of 7 recorded protein targets

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.

hypertrophic cardiomyopathy0.88

Genetic · overall 0.83

Abnormality of the cardiovascular system0.83

Genetic · overall 0.50

Rare familial disorder with hypertrophic cardiomyopathy0.83

Genetic literature · overall 0.53

familial hypertrophic cardiomyopathy0.81

Genetic · overall 0.50

cardiomyopathy0.69

Genetic · overall 0.43

Highest-confidence therapeutic associations

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

cardiovascular disorder0.76

Clinical · overall 0.46

heart failure0.63

Clinical · overall 0.39

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

chondrodysplasia Blomstrand type0.33

Genetic

metaphyseal chondrodysplasia, Jansen type0.32

Genetic

Eiken syndrome0.31

Genetic

Show all associations
hypertrophic cardiomyopathy0.83
Rare familial disorder with hypertrophic cardiomyopathy0.53
Abnormality of the cardiovascular system0.50
familial hypertrophic cardiomyopathy0.50
cardiovascular disorder0.46
cardiomyopathy0.43
heart failure0.39
chondrodysplasia Blomstrand type0.33
metaphyseal chondrodysplasia, Jansen type0.32
Eiken syndrome0.31

Open Targets ranks 167 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 · 3 total

OMECAMTIV MECARBILApproval

cardiovascular disorder · heart failure · heart failure

MAVACAMTENApproval

hypertrophic cardiomyopathy · cardiovascular disorder · hypertrophic cardiomyopathy

DANICAMTIVPhase 2 3

dilated cardiomyopathy · heart failure · heart failure

Tractability

SM · Approved DrugSM · Structure with LigandPR · Database Ubiquitination

Clinical trials

10

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein.

Omecamtiv Mecarbil Post-trial Access Protocol for Subjects Completing Study 20110203 GALACTIC-HFPHASE3

WITHDRAWN · via omecamtiv mecarbil · NCT04464525

A Double-blind, Randomized, Placebo-controlled, Multicenter Study to Evaluate the Safety and Efficacy of IV Infusion Treatment With Omecamtiv Mecarbil in Subjects With Left Ventricular Systolic Dysfunction Hospitalized for Acute Heart FailurePHASE2

COMPLETED · via omecamtiv mecarbil · NCT01300013

Single-dose and Randomized, Single-center, Placebo- and Active-controlled, Crossover Study to Assess the Effect of Omecamtiv Mecarbil (OM) on QT/QTc Intervals in Healthy SubjectsPHASE1

COMPLETED · via omecamtiv mecarbil · NCT04175808

A Phase 1, Single Center Double-blind, Randomized, Placebo-controlled Study to Evaluate the Pharmacokinetics and Safety of Omecamtiv Mecarbil in Healthy Japanese SubjectsPHASE1

COMPLETED · via omecamtiv mecarbil · NCT02601001

A Multi-Center, Double-Blind, Randomized, Placebo-Controlled Trial to Assess Efficacy and Safety of Omecamtiv Mecarbil in Patients With Symptomatic Heart Failure With Severely Reduced Ejection Fraction (COMET-HF)PHASE3

RECRUITING · via omecamtiv mecarbil · NCT06736574

A Double-blind, Randomized, Placebo-controlled, Multicenter Study to Assess the Effect of Omecamtiv Mecarbil on Exercise Capacity in Subjects With Heart Failure With Reduced Ejection Fraction and Decreased Exercise TolerancePHASE3

COMPLETED · via omecamtiv mecarbil · NCT03759392

Show remaining trials (4)
A Double-blind, Randomized, Placebo-controlled, Multicenter Study to Evaluate the Safety, Pharmacokinetics, and Efficacy of Omecamtiv Mecarbil in Japanese Subjects With Heart Failure With Reduced Ejection FractionPHASE2

COMPLETED · via omecamtiv mecarbil · NCT02695420

A Double-blind, Randomized, Placebo-controlled, Multicenter Study to Assess the Efficacy and Safety of Omecamtiv Mecarbil on Mortality and Morbidity in Subjects With Chronic Heart Failure With Reduced Ejection Fraction (GALACTIC-HF)PHASE3

COMPLETED · via omecamtiv mecarbil · NCT02929329

An Open Label, Multiple Dose Study to Investigate the Pharmacokinetics of Omecamtiv Mecarbil Administered Orally to Patients With Stable Heart FailurePHASE2

WITHDRAWN · via omecamtiv mecarbil · NCT01077167

A First-in-Man, Phase I, Double-Blind, Randomized, Four-Way Crossover, Placebo-Controlled, Dose-Escalation, Pharmacokinetic and Pharmacodynamic Study of CK-1827452 (Omecamtiv Mecarbil) in Healthy VolunteersPHASE1

COMPLETED · via omecamtiv mecarbil · NCT01380223

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.

hypertrophic cardiomyopathyWell supported
0.97
agreement 0.86–1.00
Genetic55%Clinical44%Literature2%Genetic literaturedup

Open Targets aggregate 0.83 · 3 independent evidence families · 1 not counted as duplicate

Abnormality of the cardiovascular systemWell supported
0.83
agreement 0.71–0.95
Genetic100%

Open Targets aggregate 0.50 · 1 independent evidence family

familial hypertrophic cardiomyopathyWell supported
0.81
agreement 0.68–0.95
Genetic99%Literature1%

Open Targets aggregate 0.50 · 2 independent evidence families

cardiomyopathyModerately supported
0.70
agreement 0.56–0.84
Genetic97%Literature4%

Open Targets aggregate 0.43 · 2 independent evidence families

Rare familial disorder with hypertrophic cardiomyopathyModerately supported
0.66
agreement 0.51–0.82
Genetic literature100%Geneticdup

Open Targets aggregate 0.53 · 1 independent evidence family · 1 not counted as duplicate

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

1

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 publication2020-11-13
    Cardiac Myosin Activation with Omecamtiv Mecarbil in Systolic Heart Failure.

    The New England journal of medicine · 2021 · 443 citations · Europe PMC · via omecamtiv mecarbil

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.