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Protein / target

Inositol monophosphatase 1

Encoded byIMPA1P29218Homo sapiensSwiss-Prot
UniProt: P29218Ensembl: ENSG00000133731HGNC: HGNC:6050NCBI Gene: 3612
Clinically validated
Therapeutic maturity
2
Approved medicines
Open Targets target-level
View by indication →
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Inositol monophosphate 1-phosphatase

Strongest disease association

Autosomal recessive non-syndromic intellectual disability

Via encoding gene IMPA1 · Genetic evidence · score 0.61

Therapeutic position

Established drug 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

Phosphatase involved in the dephosphorylation of myo-inositol monophosphates to generate myo-inositol.

View complete UniProt function annotation

Phosphatase involved in the dephosphorylation of myo-inositol monophosphates to generate myo-inositol (PubMed:17068342, PubMed:8718889, PubMed:9462881). Is also able to dephosphorylate scyllo-inositol-phosphate, myo-inositol 1,4-diphosphate, scyllo-inositol-1,3-diphosphate and scyllo-inositol-1,4-diphosphate (PubMed:17068342). Also dephosphorylates in vitro other sugar-phosphates including D-galactose-1-phosphate, glucose-1-phosphate, glucose-6-phosphate, fructose-1-phosphate, beta-glycerophosphate and 2'-AMP (PubMed:17068342, PubMed:8718889, PubMed:9462881). Responsible for the provision of inositol required for synthesis of phosphatidylinositols and polyphosphoinositides, and involved in maintaining normal brain function (PubMed:26416544, PubMed:8718889). Has been implicated as the pharmacological target for lithium (Li(+)) action in brain, which is used to treat bipolar affective disorder (PubMed:17068342). Is equally active with 1D-myo-inositol 1-phosphate, 1D-myo-inositol 3-phosphate and D-galactose 1-phosphate (PubMed:9462881)

Subcellular location

Cytoplasm
Domains and Gene Ontology detail (21)

Gene Ontology

  • Ccytoplasm
  • Ccytosol
  • Ffructose-1-phosphatase activity
  • Fglucose-1-phosphatase activity
  • Fglucose-6-phosphatase activity
  • Fglycerol-2-phosphatase activity
  • Fidentical protein binding
  • Finositol monophosphate 1-phosphatase activity
  • Finositol monophosphate 3-phosphatase activity
  • Finositol monophosphate 4-phosphatase activity
  • Finositol monophosphate phosphatase activity
  • Flithium ion binding

277 aa · 30 kDa · 3 isoforms

Biological roles

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

Metabolic enzyme activityGO
View supporting evidence

Metabolic enzyme activity

  • ·inositol metabolic process
  • ·phosphate-containing compound metabolic process

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

Approved medicines with mapped indications

1 medicine · 2 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.

Bipolar Disorder1 medicine
lithium carbonate
Depressive Disorder1 medicine
lithium carbonate

2 medicines meet Open Targets' target-level approved-medicine definition; the 1 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

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.

lithium carbonate
Narrow target profileApprovedInhibitor

Inositol-1(or 4)-monophosphatase 1 inhibitor

Indicated for Bipolar Disorder, Depressive Disorder

Direct interaction with this protein · 1 of 3 recorded protein targets — narrow recorded profile

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 IMPA1

Gene-level evidence surfaced through the gene IMPA1that 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.

Bipolar Disorder
0.75Moderately supported

Clinical evidence dominant · Open Targets 0.61

Autosomal recessive non-syndromic intellectual disability
0.61Moderately supported

Genetic evidence dominant · Open Targets 0.37

Neurodegenerative Diseases
0.27Preliminary

Pathway evidence dominant · Open Targets 0.41 · no direct causal or clinical evidence

View evidence synthesis (3)
Bipolar DisorderModerately supported
0.75
agreement 0.59–0.90
Clinical98%Literature2%

Open Targets aggregate 0.61 · 2 independent evidence families

Autosomal recessive non-syndromic intellectual disabilityModerately supported
0.61
agreement 0.49–0.73
Genetic100%

Open Targets aggregate 0.37 · 1 independent evidence family

Neurodegenerative DiseasesPreliminary
0.27
agreement 0.04–0.50
Pathway100%

Open Targets aggregate 0.41 · 1 independent evidence family · no direct causal or clinical evidence

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
Bipolar Disorder0.61
Neurodegenerative Diseases0.41
Autosomal recessive non-syndromic intellectual disability0.37

Drug development

2 compounds recorded · 2 approved

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 (1 with a mapped approved indication, shown above): these count different sets and are not a subset relation.

View all recorded compounds (2)
LITHIUM CITRATEApproval
LITHIUM CARBONATEApproval

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 molecules — Strong

Approved Drug and Structure with Ligand support this modality.

Protein degraders — Emerging

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

View underlying tractability evidence (6)
SM · Approved DrugSM · Structure with LigandSM · High-Quality PocketSM · Druggable FamilyPR · Database UbiquitinationPR · Half-life Data

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.

Lithium Versus Lamotrigine in Bipolar Disorder, Type II - a Single Blinded Randomized Controlled Trial (the LiLa-Bipolar RCT)PHASE4

RECRUITING · via lithium carbonate · NCT06184581

Effect of Lithium Carbonate on Postoperative Sleep and Cognitive Function in Patients Undergoing Heart Valve Surgery With Cardiopulmonary BypassPHASE4

RECRUITING · via lithium carbonate · NCT05593627

Cornelia De Lange Syndrome: Assessing Positive Effects of Lithium TreatmentPHASE2/PHASE3

RECRUITING · via lithium carbonate · NCT06789783

A Randomized, Balanced, Phase 1/2A, Multiple-dose, Open-label, Two-treatment, Two-period, Two-sequence, Crossover, Relative Bioavailability Study to Investigate Lithium Brain/Plasma Pharmacokinetics and Safety of an AL001 Oral Capsule Compared to a Marketed Immediate-release Lithium Carbonate Capsule in Subjects With Bipolar I DisorderPHASE1/PHASE2

RECRUITING · via lithium carbonate · NCT07540338

View all trials (26)
Sequenced Treatment Alternatives to Relieve Adolescent Depression (STAR-AD): a Pragmatic Clinical TrialPHASE1/PHASE2

RECRUITING · via lithium carbonate · NCT05814640

Effect of Lithium Carbonate on Postoperative Sleep in Patients Undergoing Videoassisted Thoracic SurgeryPHASE4

COMPLETED · via lithium carbonate · NCT04479566

Effect of Regulated Add -on Sodium Chloride Intake on Stabilization of Serum Lithium Concentration in Bipolar Disorder: A Randomized Controlled TrialPHASE4

COMPLETED · via lithium carbonate · NCT04222816

Evaluation of Brain and Cognitive Changes in Older Adults With MCI Taking Lithium to Prevent Alzheimer Type DementiaPHASE4

COMPLETED · via lithium carbonate · NCT03185208

Clinical Psychopharmacology Division Institute of Mental Health, Peking UniversityPHASE4

UNKNOWN · via lithium carbonate · NCT03148535

Lithium in Cardiac Surgery Related Acute Kidney Injury: A Pilot StudyPHASE4

UNKNOWN · via lithium carbonate · NCT03056248

A Prospected Randomized Multicenter Clinical Trial of Lithium Carbonate Combined With Neo-adjuvant Chemotherapy to Treat OsteosarcomaPHASE4

UNKNOWN · via lithium carbonate · NCT01669369

Cost- Effectiveness and Quality of Life Assessment in Bipolar Disorder Depressive EpisodePHASE4

COMPLETED · via lithium carbonate · NCT02918097

Lithium Use for Bipolar Disorder (LiTMUS): A Randomized Controlled Effectiveness TrialPHASE4

COMPLETED · via lithium carbonate · NCT00667745

Treatment of Bipolar Type II Major DepressionPHASE4

COMPLETED · via lithium carbonate · NCT00602537

Acute Antidepressant Therapy in Bipolar II Major DepressionPHASE4

COMPLETED · via lithium carbonate · NCT00641927

An Open-labeled, Parallel-group, Single-blinded (Rater) Pilot Study to Investigate the Neuroprotective Effects of of Low-dose Lithium in Young Subjects at Ultra High Risk (UHR) of Developing a First-episode Psychotic DisorderPHASE4

COMPLETED · via lithium carbonate · NCT00202306

Treatment of Geriatric Bipolar Mood Disorders: A Pilot StudyPHASE4

COMPLETED · via lithium carbonate · NCT00177567

Investigation of Lithium on Signal Transduction, Gene Expression and Brain Myo-Inositol Levels in Manic PatientsPHASE4

COMPLETED · via lithium carbonate · NCT00870311

Effect of Lithium in Patients With Autism Spectrum Disorder and Phelan-McDermid Syndrome (SHANK3 Haploinsufficiency): Pilot Study.PHASE3

COMPLETED · via lithium carbonate · NCT04623398

A Lithium-Based Medication to Improve Neurological Outcomes After Surgical Carotid Reconstruction: A Double-Blind, Placebo Control Randomized Trial (BINOS)PHASE3

TERMINATED · via lithium carbonate · NCT05126238

A Multi-arm, Adaptive, Group-sequential Trial NETwork to Evaluate Drug Efficacy in Patients With Amyotrophic Lateral Sclerosis (ALS)PHASE3

TERMINATED · via lithium carbonate · NCT06008249

Evaluation of Lithium Efficacy Against Chemotherapy Induced Neutropenia in Breast Cancer PatientsPHASE3

COMPLETED · via lithium carbonate · NCT05221593

Randomized Clinical Trial to Assess the Safety and Efficacy of Lithium Carbonate in Patients With Spinocerebellar Ataxia Type 3PHASE2/PHASE3

COMPLETED · via lithium carbonate · NCT01096082

A Randomized, Double-blind, Placebo Controlled Study of the Efficacy of Lithium for the Treatment of Pediatric Mania Followed by an Open Label Long-term Safety Period, Double-blind, Placebo-controlled Discontinuation Phase, and Open Label Restabilization Period.PHASE2/PHASE3

COMPLETED · via lithium carbonate · NCT01166425

The Neurotrophic Effects of Lithium Carbonate Following Stroke: A Feasibility StudyPHASE3

COMPLETED · via lithium carbonate · NCT01112813

A Randomised, Multi-Centre Study to Compare the Efficacy and Safety of Extended Release Quetiapine Fumarate (Seroquel XR TM) Tablets as Mono-Therapy or in Combination With Lithium in the Treatment of Patients With Acute Bipolar DepressionPHASE3

COMPLETED · via lithium carbonate · NCT00883493

A Multicenter, Double-Blind, Placebo-Controlled, Study to Investigate the Safety and Efficacy of Lithium in Combination With Riluzole in Volunteers With Amyotrophic Lateral Sclerosis (ALS)PHASE2/PHASE3

TERMINATED · via lithium carbonate · NCT00818389

A Randomised, 6-week, Multicentre, Open-label, Rater-blinded Parallel Group Study Comparing Quetiapine Extended Release Monotherapy and Augmentation With Lithium Augmentation in Patients With Treatment Resistant DepressionPHASE3

COMPLETED · via lithium carbonate · NCT00789854

Double-Blind, Randomized, Placebo-Controlled, Parallel-Group, Multicenter, Efficacy and Safety Study of Lithium in Bipolar I DisorderPHASE3

UNKNOWN · via lithium carbonate · NCT00422331

Comparing the Safety and Effectiveness of a Mood Stabilizing Medication, an Antidepressant Medication, and a Combination of Both Medications to Treat Symptoms of Bipolar Type II DepressionPHASE3

COMPLETED · via lithium carbonate · NCT00276965

ClinicalTrials.gov via the drug-target graph.

What's happening now

10

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. Trial status changed2026-07-29

    A Randomized, Balanced, Phase 1, Multiple-dose, Open-label, Two-treatment, Two-period, Two-sequence, Crossover, Relative Bioavailability Study to Investigate Lithium Brain/Plasma Pharmacokinetics and Safety of an AL001 Oral Capsule Compared to a Marketed Immediate-release Lithium Carbonate Capsule in Healthy Adult Subjects

    Status changed to Completed · ClinicalTrials.gov · via lithium carbonate

  2. Label change2026-07-13

    Label change: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

  3. Label change2020-02-14

    Label change: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

  4. Label change2020-02-14

    Label change: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

  5. Label change2020-02-14

    Label change: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

  6. Label change2012-03-06

    Label change: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

  7. New publication2011-11-22
    Efficacy and safety of lithium carbonate treatment of chronic spinal cord injuries: a double-blind, randomized, placebo-controlled clinical trial.

    Spinal cord · 2012 · 41 citations · Europe PMC · via lithium carbonate

  8. Label change2007-12-26

    Label change: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

  9. Label change2007-09-28

    Label change: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

  10. Regulatory approval2004-10-28

    Approval: LITHIUM CARBONATE (ANDA076832)

    fda · regulatory · fda · via lithium carbonate

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.