TNNI1

gene
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Also known as ssTnI

Summary

TNNI1 (troponin I1, slow skeletal type, HGNC:11945) is a protein-coding gene on chromosome 1q32.1, encoding Troponin I, slow skeletal muscle (P19237). Troponin I is the inhibitory subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity.

Troponin proteins associate with tropomyosin and regulate the calcium sensitivity of the myofibril contractile apparatus of striated muscles. Troponin I (TnI), along with troponin T (TnT) and troponin C (TnC), is one of 3 subunits that form the troponin complex of the thin filaments of striated muscle. TnI is the inhibitory subunit; blocking actin-myosin interactions and thereby mediating striated muscle relaxation. The TnI subfamily contains three genes: TnI-skeletal-fast-twitch, TnI-skeletal-slow-twitch, and TnI-cardiac. The TnI-fast and TnI-slow genes are expressed in fast-twitch and slow-twitch skeletal muscle fibers, respectively, while the TnI-cardiac gene is expressed exclusively in cardiac muscle tissue. This gene encodes the Troponin-I-skeletal-slow-twitch protein. This gene is expressed in cardiac and skeletal muscle during early development but is restricted to slow-twitch skeletal muscle fibers in adults. The encoded protein prevents muscle contraction by inhibiting calcium-mediated conformational changes in actin-myosin complexes.

Source: NCBI Gene 7135 — RefSeq curated summary.

At a glance

  • Gene–disease (curated): arthrogryposis (Moderate, GenCC) — +2 more curated relationships
  • Clinical variants (ClinVar): 32 total
  • MANE Select transcript: NM_003281

Identifiers

Gene identifiers

FieldValue
HGNC IDHGNC:11945
Approved symbolTNNI1
Nametroponin I1, slow skeletal type
Location1q32.1
Locus typegene with protein product
StatusApproved
AliasesssTnI
Ensembl geneENSG00000159173
Ensembl biotypeprotein_coding
OMIM191042
Entrez7135

Gene structure

Transcript identifiers

Ensembl transcripts: 6 — 6 protein_coding

ENST00000336092, ENST00000361379, ENST00000367312, ENST00000555340, ENST00000555948, ENST00000556362

RefSeq mRNA: 1 — MANE Select: NM_003281 NM_003281

CCDS: CCDS1411

Canonical transcript exons

ENST00000361379 — 9 exons

ExonStartEnd
ENSE00001074229201410326201410435
ENSE00001074235201413032201413121
ENSE00001350131201417783201417812
ENSE00001957519201403784201409250
ENSE00003526310201415213201415254
ENSE00003535850201417116201417119
ENSE00003561878201414518201414649
ENSE00003787328201411357201411533
ENSE00003843411201421673201421730

Expression profiles

Bgee: expression breadth ubiquitous, 183 present calls, max score 99.93.

FANTOM5 (CAGE): breadth broad, TPM avg 15.7471 / max 3108.0544, expressed in 247 samples.

FANTOM5 promoters (5 alternative TSS)

Promoter IDTPM avgSamples expressed
1664815.4919246
166500.174147
166510.038222
166490.027916
166520.01507

Top tissues by expression

293 total, by Bgee expression score (0-100, higher = more expressed):

TissueAnatomy IDExpression scoreQuality
skeletal muscle tissue of rectus abdominisUBERON:000451199.93gold quality
skeletal muscle tissue of biceps brachiiUBERON:000450299.91gold quality
diaphragmUBERON:000110399.89gold quality
triceps brachiiUBERON:000150999.89gold quality
hindlimb stylopod muscleUBERON:000425299.89gold quality
gluteal muscleUBERON:000200099.88gold quality
biceps brachiiUBERON:000150799.84gold quality
vastus lateralisUBERON:000137999.77gold quality
skeletal muscle tissueUBERON:000113499.71gold quality
quadriceps femorisUBERON:000137799.61gold quality
gastrocnemiusUBERON:000138899.54gold quality
body of tongueUBERON:001187699.27gold quality
deltoidUBERON:000147698.96gold quality
tibialis anteriorUBERON:000138598.74gold quality
muscle organUBERON:000163098.24gold quality
muscle of legUBERON:000138397.66gold quality
muscle tissueUBERON:000238594.55gold quality
right atrium auricular regionUBERON:000663193.08gold quality
tongueUBERON:000172392.04gold quality
cardiac atriumUBERON:000208192.04gold quality
superior surface of tongueUBERON:000737186.72gold quality
apex of heartUBERON:000209886.00gold quality
cardiac muscle of right atriumUBERON:000337983.69gold quality
pharyngeal mucosaUBERON:000035583.47gold quality
heartUBERON:000094882.52gold quality
heart left ventricleUBERON:000208481.11gold quality
cardiac ventricleUBERON:000208280.82gold quality
myocardiumUBERON:000234977.46gold quality
trabecular bone tissueUBERON:000248377.27gold quality
heart right ventricleUBERON:000208076.91gold quality

Single-cell (SCXA)

Detected in 4 experiment(s), a significant marker in 4.

ExperimentMarker?Max mean expression
E-HCAD-56yes3139.36
E-GEOD-114530yes1834.54
E-HCAD-10yes18.94
E-ANND-3no0.00

Regulation

Is transcription factor: no

Upstream regulators (CollecTRI, top): NVL

miRNA regulators (miRDB)

203 targeting TNNI1, top 30 by miRDB confidence (max_score; target_count = how many genes the miRNA targets in total — lower means more specific):

miRNAMax scoreAvg scoremiRNA target_count
HSA-MIR-4455100.0065.481587
HSA-MIR-4533100.0069.482758
HSA-MIR-8485100.0077.574731
HSA-MIR-6867-5P100.0082.213464
HSA-MIR-4692100.0067.322066
HSA-MIR-3925-3P100.0069.951237
HSA-MIR-4476100.0068.182030
HSA-MIR-6876-5P100.0067.682126
HSA-MIR-5193100.0067.261744
HSA-MIR-3613-3P100.0076.367965
HSA-MIR-4481100.0066.421669
HSA-MIR-574-5P100.0066.01989
HSA-MIR-6758-5P100.0066.211470
HSA-MIR-6856-5P100.0065.471298
HSA-MIR-451499.9967.101870
HSA-MIR-453199.9969.703181
HSA-MIR-371B-5P99.9975.344759
HSA-MIR-318599.9968.121959
HSA-MIR-607799.9968.042299
HSA-MIR-366299.9973.825684
HSA-MIR-6870-5P99.9968.552115
HSA-MIR-373-5P99.9875.364753
HSA-MIR-616-5P99.9875.584775
HSA-MIR-4715-3P99.9866.03670
HSA-MIR-569899.9768.492029
HSA-MIR-4723-5P99.9768.702034
HSA-MIR-7111-5P99.9768.482062
HSA-MIR-448799.9664.581252
HSA-MIR-568899.9673.234504
HSA-MIR-495-3P99.9672.814197

Literature-anchored findings (GeneRIF, showing 21)

  • troponin I phosphorylation has a role in protein kinase C-mediated enhanced contractile performance of myocytes (PMID:12815045)
  • MEF2 activation of the troponin I slow enhancer is repressed by hMusTRD1alpha1 (PMID:12857748)
  • Low expression of ssTnI was found in 60% of patients in sinus rhythm or paroxysmal AF and in 8% of patients with chronic AF. Relative ssTnI mRNA expression was significantly lower in patients with AF than in those in sinus rhythm. (PMID:15289369)
  • These results suggest that this R21C mutation in TnI affects the Ca(2+)-sensitizing effect of Tn, the ability of TnI to be readily phosphorylated by PKA and the stability of TnI to calpain. (PMID:16005017)
  • A revised method of troponin exchange in pemeabilized cardiac trabeculae using vanadate: functional consequences of a HCM-causing mutation in troponin I. (PMID:17051347)
  • a localized N-terminal region of TnI comprised of amino acids 33-80, which interacts with C-terminal regions of cTnC and cTnT, is of particular significance in transducing signaling of thin filament activation by strong cross-bridges (PMID:17099250)
  • Elevated post-operative troponin 1 levels predict long-term mortality in older patients undergoing emergency orthpedic surgery. (PMID:19811558)
  • Evaluated the prevalence of TNN13 gene mutations in sudden death caused by cardiomyopathy (CM); in dilated CM cases, a new missense mutation Pro16Thr was detected. A single nucleotide polymorphism at -8 position of intron 3 was identified. (PMID:20817590)
  • sTnI as a sensitive marker of skeletal muscle injury. (PMID:22323298)
  • Elevations of troponin I and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are common in patients with atrial fibrillation and independently related to increased risks of stroke and mortality. (PMID:22374183)
  • Data suggest that mutation A162H in switch region of troponin I induces transitory curved conformation and promotes contraction of troponin I bound to regulatory domain of troponin C; this is countered by residue E164 to ensure proper relaxation. (PMID:25996354)
  • CT-1 was found to be associated with Tn-I, which is used to detect myocardial damage after OPCAB surgery. CT-1 may also be used to detect myocardial damage. (PMID:26334851)
  • GDF-15, sST2, and hs-TnI are associated with incident cardiovascular disease and heart failure (PMID:26972631)
  • Measuring mean platelet volume in conjunction with troponin I levels improves the diagnostic value of troponin I in acute coronary syndrome. (PMID:27524214)
  • Ultrasensitive troponin I was detectable in almost all individuals of a study sample reflecting middle-aged to elderly European general population. Ultrasensitive troponin concentrations exhibit an independent, graded, positive relation with incident CHD [coronary heart disease]. (PMID:28585121)
  • Studied use of serum levels of Troponin I as a predictive biomarker for diagnosis of left ventricular systolic dysfunction after anthracycline treatment in breast cancer. (PMID:28718245)
  • Troponin I levels at intensive care unit admission are a strong independent predictor of dialysis needs in sepsis. (PMID:30453890)
  • Cardiac Troponin I Is an Independent Predictor for Mortality in Hospitalized Patients With COVID-19. (PMID:32539541)
  • Postoperative troponin increases after noncardiac surgery are associated with raised neurofilament light: a prospective observational cohort study. (PMID:33158499)
  • Elevation of fast but not slow troponin I in the circulation of patients with Becker and Duchenne muscular dystrophy. (PMID:33683712)
  • Pathogenic TNNI1 variants disrupt sarcomere contractility resulting in hypo- and hypercontractile muscle disease. (PMID:38569017)

Cross-species orthologs

9 orthologs

OrganismSymbolGene ID
danio_reriotnni1aENSDARG00000000474
danio_reriotnni1bENSDARG00000052708
mus_musculusTnni1ENSMUSG00000026418
rattus_norvegicusTnni1ENSRNOG00000009073
drosophila_melanogasterwupAFBGN0283471
caenorhabditis_elegansWBGENE00006584
caenorhabditis_elegansWBGENE00006585
caenorhabditis_elegansWBGENE00006586
caenorhabditis_elegansWBGENE00006764

Paralogs (2): TNNI3 (ENSG00000129991), TNNI2 (ENSG00000130598)

Protein

Protein identifiers

Troponin I, slow skeletal muscleP19237 (reviewed: P19237)

Alternative names: Troponin I, slow-twitch isoform

All UniProt accessions (4): P19237, G3V3L5, G3V489, G3V4F8

UniProt curated annotations — full annotation on UniProt →

Function. Troponin I is the inhibitory subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity.

Subunit / interactions. Binds to actin and tropomyosin.

Tissue specificity. Highest levels observed in human skeletal muscle (e.g. gastrocnemious muscle), differentiated cultures of primary human muscle cells and rhabdomyosarcoma cells cultured in low serum medium. Expressed in C2 muscle cell myoblasts and myotubes.

Similarity. Belongs to the troponin I family.

RefSeq proteins (1): NP_003272* (*=MANE)

Domains & families (InterPro)

IDNameType
IPR001978TroponinFamily
IPR038077Troponin_sfHomologous_superfamily
IPR050875Troponin_IFamily

Pfam: PF00992

UniProt features (13 total): sequence conflict 6, region of interest 2, modified residue 2, initiator methionine 1, chain 1, sequence variant 1

Structure

Experimental structures (PDB)

0 structures.

Predicted structure (AlphaFold)

ModelpLDDTFraction very-high
AF-P19237-F178.440.47

Functional residue map

Curated UniProt residues grouped by drug-discovery relevance — catalytic, ligand-binding, modification, and mutation-validated positions. Source: UniProtKB sequence features.

Post-translational modifications (2): 2, 58

Function

Pathways and Gene Ontology

Reactome pathways

1 pathways

IDPathway
R-HSA-390522Striated Muscle Contraction

MSigDB gene sets: 180 (showing top): GOBP_CARDIAC_CHAMBER_DEVELOPMENT, GGGACCA_MIR133A_MIR133B, GOBP_MUSCLE_TISSUE_DEVELOPMENT, GOBP_CIRCULATORY_SYSTEM_PROCESS, GOBP_CARDIAC_CHAMBER_MORPHOGENESIS, GOBP_SKELETAL_MUSCLE_ADAPTATION, GCANCTGNY_MYOD_Q6, AREB6_03, GRAESSMANN_APOPTOSIS_BY_DOXORUBICIN_UP, GRAESSMANN_RESPONSE_TO_MC_AND_DOXORUBICIN_UP, TGACCTY_ERR1_Q2, GOBP_MULTICELLULAR_ORGANISMAL_MOVEMENT, MEF2_02, GOBP_SKELETAL_MUSCLE_CONTRACTION, COUP_01

GO Biological Process (5): skeletal muscle contraction (GO:0003009), regulation of striated muscle contraction (GO:0006942), transition between fast and slow fiber (GO:0014883), ventricular cardiac muscle tissue morphogenesis (GO:0055010), cardiac muscle contraction (GO:0060048)

GO Molecular Function (2): actin binding (GO:0003779), protein binding (GO:0005515)

GO Cellular Component (2): cytosol (GO:0005829), troponin complex (GO:0005861)

Reactome top-level categories

Rollup of top-1 pathways:

CategoryPathways
Muscle contraction1

GO top-level categories

Rollup of top GO terms by namespace:

CategoryTerms
striated muscle contraction3
musculoskeletal movement1
regulation of muscle contraction1
regulation of skeletal muscle adaptation1
cardiac ventricle morphogenesis1
ventricular cardiac muscle tissue development1
cardiac muscle tissue morphogenesis1
heart contraction1
cytoskeletal protein binding1
binding1
cytoplasm1
cellular anatomical structure1
striated muscle thin filament1
protein-containing complex1

Protein interactions and networks

STRING

1170 interactions, top by confidence (×1000):

Protein AProtein BPartner UniProtScore
TNNI1TNNT1P13805967
TNNI1TNNT3P45378935
TNNI1TNNT2P45379909
TNNI1TNNC1P02590868
TNNI1MYH7P12883817
TNNI1TPM3P06753749
TNNI1MYL3P08590717
TNNI1MYL7Q01449707
TNNI1TNNC2P02585697
TNNI1MYL2P10916682
TNNI1MYH7BA7E2Y1655
TNNI1MYBPC3Q14896653
TNNI1MYH6P13533651
TNNI1ACTN3Q08043631
TNNI1MYL11Q96A32629

IntAct

138 interactions, top by confidence:

ABTypeScore
PNMA1TNNI1psi-mi:“MI:0915”(physical association)0.720
TNNI1PNMA1psi-mi:“MI:0915”(physical association)0.720
TNNI1TNNC1psi-mi:“MI:0915”(physical association)0.700
TNNI1MDFIpsi-mi:“MI:0915”(physical association)0.560
MDFITNNI1psi-mi:“MI:0915”(physical association)0.560
MFAP1TNNI1psi-mi:“MI:0915”(physical association)0.560
EAF1TNNI1psi-mi:“MI:0915”(physical association)0.560
TNNI1psi-mi:“MI:0915”(physical association)0.560
TNNT1TNNI1psi-mi:“MI:0915”(physical association)0.560
TRIM41TNNI1psi-mi:“MI:0915”(physical association)0.560
MCRS1TNNI1psi-mi:“MI:0915”(physical association)0.560
PIK3R3TNNI1psi-mi:“MI:0915”(physical association)0.560
POLR1CTNNI1psi-mi:“MI:0915”(physical association)0.560
EFCAB2TNNI1psi-mi:“MI:0915”(physical association)0.560
KIFC3TNNI1psi-mi:“MI:0915”(physical association)0.560
ANKRD11TNNI1psi-mi:“MI:0915”(physical association)0.560

BioGRID (59): TNNI1 (Two-hybrid), TNNI1 (Two-hybrid), TNNI1 (Two-hybrid), PNMA1 (Two-hybrid), CCDC85B (Two-hybrid), MYH3 (Co-fractionation), MYH6 (Co-fractionation), MYH7 (Co-fractionation), TNNI1 (Co-fractionation), TPM1 (Co-fractionation), TPM2 (Co-fractionation), TNNI1 (Reconstituted Complex), TNNI1 (Affinity Capture-MS), TNNI1 (Two-hybrid), TNNI1 (Two-hybrid)

ESM2 similar proteins: A2AQ19, B5G1C4, B5XE27, O43395, O43768, O75391, O95983, P19237, P56211, P56212, P60840, P60841, P68210, P68211, Q0MUU2, Q13123, Q13435, Q1L8X2, Q28055, Q28GU6, Q2KI76, Q2KIA6, Q3UJB0, Q3ZBD4, Q5NVI3, Q5R5F1, Q5R5J3, Q5RAD5, Q5RB90, Q5ZIF8, Q5ZJ85, Q5ZLY8, Q66HG8, Q6DEB4, Q6GQG3, Q6NVR1, Q712U5, Q712U6, Q7TNE3, Q7ZXH9

Diamond homologs: O44572, P02643, P02645, P02646, P08057, P13412, P13413, P19237, P19429, P23693, P27672, P27673, P27768, P36188, P48787, P48788, P50754, P68246, P68247, Q20334, Q5PYI0, Q7M3Y3, Q863B6, Q8MKD5, Q969A1, Q9GYF1, Q9WUZ5, P05547, Q9XUN9

SIGNOR signaling

1 interactions.

AEffectBMechanism
TRIM63“down-regulates quantity by destabilization”TNNI1polyubiquitination

Disease & clinical

Clinical variants and AI predictions

ClinVar

32 variants total. Per-class counts are floors (≥ shown; pagination cap):

ClassificationCount (floor)
Pathogenic0
Likely pathogenic0
Uncertain significance24
Likely benign1
Benign0

Top pathogenic / likely-pathogenic (0)

SpliceAI

1103 predictions. Top by Δscore:

VariantEffectΔscore
1:201410321:GGTAC:Gdonor_loss1.0000
1:201410322:GTACC:Gdonor_loss1.0000
1:201410323:TA:Tdonor_loss1.0000
1:201410324:A:Cdonor_loss1.0000
1:201410325:C:Adonor_loss1.0000
1:201410325:CCT:Cdonor_gain1.0000
1:201410327:T:TAdonor_gain1.0000
1:201410431:CGCTC:Cacceptor_gain1.0000
1:201410433:CTC:Cacceptor_gain1.0000
1:201410434:TCC:Tacceptor_loss1.0000
1:201410435:CCTG:Cacceptor_loss1.0000
1:201410436:C:CCacceptor_gain1.0000
1:201410436:CTGTA:Cacceptor_loss1.0000
1:201410437:T:Gacceptor_loss1.0000
1:201411351:CCTCA:Cdonor_loss1.0000
1:201411352:CTCA:Cdonor_loss1.0000
1:201411353:TCAC:Tdonor_loss1.0000
1:201411354:CACC:Cdonor_loss1.0000
1:201411355:A:ACdonor_gain1.0000
1:201411355:A:ATdonor_loss1.0000
1:201411355:AC:Adonor_gain1.0000
1:201411356:C:CCdonor_gain1.0000
1:201411356:CC:Cdonor_gain1.0000
1:201411356:CCTT:Cdonor_gain1.0000
1:201411370:T:TAdonor_gain1.0000
1:201411533:TC:Tacceptor_loss1.0000
1:201411534:C:CCacceptor_gain1.0000
1:201411534:CT:Cacceptor_loss1.0000
1:201413027:CTCA:Cdonor_loss1.0000
1:201413028:TCACC:Tdonor_loss1.0000

AlphaMissense

0 scored. Top likely-pathogenic:

dbSNP variants (sampled 300 via entrez): RS1000088279 (1:201406510 G>C), RS1000149941 (1:201409460 C>T), RS1000222182 (1:201410890 A>G), RS1000380388 (1:201423156 T>C), RS1000411672 (1:201420736 T>G), RS1000502463 (1:201409245 G>A,T), RS1000750348 (1:201419790 G>A,T), RS1000867065 (1:201420985 C>G,T), RS1001298673 (1:201420676 G>A), RS1001757375 (1:201405248 G>C,T), RS1002099324 (1:201422232 C>T), RS1002233342 (1:201408868 G>C), RS1002455982 (1:201421903 G>A,T), RS1002566866 (1:201407581 C>A,T), RS1002583056 (1:201414331 A>G)

Disease associations

OMIM: gene MIM:191042 | disease phenotypes:

GenCC curated gene-disease

DiseaseClassificationInheritance
arthrogryposisModerateAutosomal dominant

ClinGen Gene-Disease Validity (2)

Expert-panel classifications — Definitive > Strong > Moderate > Limited > Disputed > Refuted.

DiseaseClassificationInheritance
childhood-onset nemaline myopathyLimitedAR
nemaline myopathyLimitedAD

Mondo (1): arthrogryposis (MONDO:0008779)

Orphanet (0):

HPO phenotypes

0 total (0 of 0 shown, HPO-id order):

GWAS associations

0 associations (top):

MeSH disease descriptors (1)

DescriptorNameTree numbers
D001176ArthrogryposisC05.550.150; C05.651.102; C05.660.077; C16.131.621.077

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (VIP=true, CPIC=false)

CTD chemical–gene interactions

17 total (human), top 17 by PubMed support.

ChemicalActions (top 5)PubMed papers
bisphenol Adecreases methylation, increases expression2
methylmercuric chlorideincreases expression1
pirinixic acidaffects binding, decreases expression, increases activity, increases expression1
tebuconazoledecreases expression1
CGP 52608affects binding, increases reaction1
incobotulinumtoxinAdecreases expression1
Resveratrolaffects cotreatment, decreases expression1
Sunitinibdecreases expression1
Benzo(a)pyreneaffects methylation, increases methylation1
Doxorubicinincreases expression1
Plant Extractsaffects cotreatment, decreases expression1
Dronabinoldecreases expression1
Tobacco Smoke Pollutiondecreases expression1
Urethanedecreases expression1
Valproic Acidaffects expression1
1-Methyl-4-phenylpyridiniumincreases expression1
Aflatoxin B1increases methylation1

Clinical trials (associated diseases)

9 trials via MONDO — disease-level, not drug-specific.

TrialPhaseStatusTitle
NCT01028833PHASE2COMPLETEDEffects of Power Mobility on Young Children With Severe Motor Impairments
NCT01144741Not specifiedTERMINATEDSurvey Study and Records Review of Treatment Outcomes in Freeman-Sheldon Syndrome
NCT01306994Not specifiedWITHDRAWNStudy of Resting and Exercising Body Functioning in Freeman-Sheldon Syndrome and Related Conditions
NCT01307475Not specifiedTERMINATEDStudy of Quality of Life in Freeman-Sheldon Syndrome and Related Conditions
NCT02218593Not specifiedCOMPLETEDWREX Outcome Study
NCT04789746Not specifiedUNKNOWNReady, Set, Go! A Physical Fitness Intervention for Children With Mobility Challenges
NCT04798378Not specifiedACTIVE_NOT_RECRUITINGNuroSleeve Powered Brace & Stimulation System to Restore Arm Function
NCT06192134Not specifiedNOT_YET_RECRUITINGContinuous Passive Motion Device for Children With Arthrogryposis
NCT07429188Not specifiedRECRUITINGImpact Study on Users of Upper Limb Assistive Devices