TNNT1: Troponin T1, Slow Skeletal Type
Essential sarcomeric protein in slow-twitch muscle fibers; mutations cause nemaline myopathy and related disorders.
Gene Information Card
| Symbol | TNNT1 |
|---|---|
| Full Name | Troponin T1, Slow Skeletal Type |
| Gene Type | Protein coding |
| Chromosomal Location | 19q13.42 |
| NCBI Gene ID | 7138 ncbi.nlm.nih.gov/gene/7138 |
| Ensembl ID | ENSG00000105048 |
| UniProt ID | P13805 |
| OMIM ID | 191041 |
| HGNC ID | 11949 |
| Aliases | TNNT1, ANM, TNT, TnTc, slow troponin T |
Description
TNNT1 encodes the slow skeletal muscle isoform of troponin T, a component of the troponin complex that regulates calcium-mediated muscle contraction. It is expressed predominantly in slow-twitch (type I) muscle fibers. Mutations in TNNT1 cause nemaline myopathy type 5 (NEM5), an autosomal recessive disorder characterized by muscle weakness, hypotonia, and rod-shaped inclusions in muscle fibers.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Nemaline myopathy 5 (NEM5) | Loss-of-function mutations in TNNT1 disrupt sarcomere assembly and calcium sensitivity, leading to muscle fiber degeneration and nemaline rod formation. | ClinVar, OMIM |
| Dilated cardiomyopathy (rare association) | Altered troponin T function may impair cardiac contractility, though evidence is limited. | NCBI Gene, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skeletal muscle (slow-twitch) | 45.2 | High |
| Heart | 1.8 | Low |
| Brain | 0.3 | Not detected |
| Liver | 0.1 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| LHCN-M2 (skeletal muscle myotubes) | 38.5 | Differentiated myotubes |
| HSMM (skeletal muscle myoblasts) | 12.1 | Undifferentiated |
| H9c2 (rat cardiomyoblasts) | 2.0 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.541G>A (p.Glu181Lys) | Missense | <0.01% | Reduced calcium sensitivity; associated with NEM5 |
| c.1A>G (p.Met1Val) | Start loss | <0.01% | Loss of protein expression; pathogenic |
| c.574C>T (p.Arg192*) | Nonsense | <0.01% | Premature truncation; loss of function |
Mutation functional classification
Loss of Function (LOF)
Most TNNT1 mutations are loss-of-function, leading to reduced or absent protein, impaired sarcomere integrity, and nemaline myopathy.
Gain of Function (GOF)
No confirmed gain-of-function mutations reported.
Dominant Negative (DN)
Not established; all known pathogenic mutations are recessive.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Troponin-mediated regulation of muscle contraction (Reactome: R-HSA-390522)
• Cardiac muscle contraction (KEGG: hsa04260)
• Skeletal muscle contraction (KEGG: hsa04261)
Protein Summary
Troponin T1 (slow skeletal) is a 278-amino-acid protein that anchors the troponin complex to tropomyosin on the thin filament of sarcomeres. It modulates calcium-dependent activation of actin-myosin cross-bridge cycling. The protein is highly expressed in slow-twitch skeletal muscle and is essential for normal muscle contraction. Mutations cause nemaline myopathy type 5.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| TNNT1 Knockout HEK293 Cell Line | EDJ-KQ15875 | Human | 7138 | Details Get a Quote |
| TNNT1 Knockout HCT 116 Cell Line | EDJ-KQ49094 | Human | 7138 | Details Get a Quote |
| TNNT1 Knockout HeLa Cell Line | EDJ-KQ49095 | Human | 7138 | Details Get a Quote |
| TNNT1 Knockout A-549 Cell Line | EDJ-KQ46871 | Human | 7138 | Details Get a Quote |
| TNNT1 Knockout Huh-7.5.1 Cell Line | EDJ-KZ55 | Human | 7138 | Details Get a Quote |
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