TNNI3 (Troponin I3, Cardiac Type)
Cardiac Troponin I: A Key Regulator of Myocardial Contraction and Biomarker for Cardiac Injury
Gene Information Card
| Symbol | TNNI3 |
|---|---|
| Full Name | Troponin I3, Cardiac Type |
| Gene Type | Protein coding |
| Chromosomal Location | 19q13.42 |
| NCBI Gene ID | 7137 ncbi.nlm.nih.gov/gene/7137 |
| Ensembl ID | ENSG00000129991 |
| UniProt ID | P19429 |
| OMIM ID | 191044 |
| HGNC ID | 11947 |
| Aliases | CMH7, RCM1, TNNC1, cTnI, CMD1FF, CMD2A, CMD1FF, CMD2A |
Description
The TNNI3 gene encodes cardiac troponin I (cTnI), a key regulatory protein of the troponin complex in cardiac muscle. cTnI inhibits actin-myosin interaction in the absence of calcium, thereby regulating myocardial contraction. Mutations in TNNI3 are associated with various cardiomyopathies, including hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), and dilated cardiomyopathy (DCM). cTnI is also a highly specific biomarker for myocardial infarction and cardiac injury.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hypertrophic Cardiomyopathy (HCM) | Missense mutations in TNNI3 disrupt calcium sensitivity and sarcomere function, leading to myocyte hypertrophy and disarray. | ClinVar, OMIM |
| Restrictive Cardiomyopathy (RCM) | Mutations impair diastolic relaxation by altering troponin I conformation, increasing myofilament calcium sensitivity. | ClinVar, OMIM |
| Dilated Cardiomyopathy (DCM) | Loss-of-function variants reduce contractile force, leading to ventricular dilation and systolic dysfunction. | ClinVar, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 194.2 | High |
| Skeletal Muscle | 0.0 | Not detected |
| Liver | 0.0 | Not detected |
| Brain | 0.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Cardiomyocytes (iPS-derived) | 195.0 | High expression |
| HeLa | 0.0 | No expression |
| HEK293 | 0.0 | No expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.433C>T (p.Arg145Trp) | Missense | Rare | Associated with HCM; increases calcium sensitivity |
| c.611G>A (p.Arg204His) | Missense | Rare | Associated with RCM; impairs relaxation |
| c.557G>A (p.Arg186Gln) | Missense | Rare | Associated with DCM; reduces contractility |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations (e.g., truncations) reduce contractile force and are linked to DCM.
Gain of Function (GOF)
Gain-of-function mutations (e.g., increased calcium sensitivity) are linked to HCM and RCM.
Dominant Negative (DN)
Dominant-negative effects occur when mutant cTnI interferes with wild-type troponin complex function, common in HCM.
View complete mutation data：
Gene Ontology (GO)
| • calcium ion binding | • actin binding |
| • troponin complex | • regulation of muscle contraction |
| • cardiac muscle contraction |
Pathways
• Cardiac muscle contraction (KEGG: hsa04260)
• Adrenergic signaling in cardiomyocytes (KEGG: hsa04261)
• Hypertrophic cardiomyopathy (KEGG: hsa05410)
• Dilated cardiomyopathy (KEGG: hsa05414)
Protein Summary
Cardiac troponin I (cTnI) is a 210-amino acid protein that binds to actin and inhibits myosin ATPase activity in the absence of calcium. Upon calcium binding to troponin C, cTnI undergoes a conformational change that allows actin-myosin interaction and contraction. cTnI is exclusively expressed in cardiac muscle, making it a specific biomarker for myocardial damage. Post-translational modifications such as phosphorylation by protein kinase A modulate its function.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| TNNI3 Knockout HEK293 Cell Line | EDJ-KQ1813 | Human | 7137 | Details Get a Quote |
| TNNI3 Knockout A-549 Cell Line | EDJ-KQ21666 | Human | 7137 | Details Get a Quote |
| TNNI3 Knockout HCT 116 Cell Line | EDJ-KQ21667 | Human | 7137 | Details Get a Quote |
| TNNI3K Knockout HEK293 Cell Line | EDJ-KQ51278 | Human | 51086 | Details Get a Quote |
| FPGT-TNNI3K Knockout HEK293 Cell Line | EDJ-KQ52479 | Human | 100526835 | Details Get a Quote |
| TNNI3 Knockout HeLa Cell Line | EDJ-KQ54680 | Human | 7137 | Details Get a Quote |
| TNNI3K Knockout HeLa Cell Line | EDJ-KQ56225 | Human | 51086 | Details Get a Quote |
| FPGT-TNNI3K Knockout HeLa Cell Line | EDJ-KQ60942 | Human | 100526835 | Details Get a Quote |
| TNNI3K Knockout A-549 Cell Line | EDJ-KQ64716 | Human | 51086 | Details Get a Quote |
| FPGT-TNNI3K Knockout A-549 Cell Line | EDJ-KQ69417 | Human | 100526835 | Details Get a Quote |
| TNNI3K Knockout HCT 116 Cell Line | EDJ-KQ73160 | Human | 51086 | Details Get a Quote |
| FPGT-TNNI3K Knockout HCT 116 Cell Line | EDJ-KQ77768 | Human | 100526835 | Details Get a Quote |
Displaying Records 1 To 12 Of 12 Records
