TNNC2: Troponin C2, Fast Skeletal Type
Key regulator of calcium-mediated muscle contraction in fast-twitch skeletal muscle fibers
Gene Information Card
| Symbol | TNNC2 |
|---|---|
| Full Name | Troponin C2, Fast Skeletal Type |
| Gene Type | protein-coding |
| Chromosomal Location | 20q13.12 |
| NCBI Gene ID | 7125 ncbi.nlm.nih.gov/gene/7125 |
| Ensembl ID | ENSG00000101489 |
| UniProt ID | P02585 |
| OMIM ID | 191039 |
| HGNC ID | 11944 |
| Aliases | TNNC, troponin C, fast skeletal muscle |
Description
TNNC2 encodes troponin C2, the calcium-binding subunit of the troponin complex in fast-twitch skeletal muscle fibers. This protein binds calcium ions released during muscle activation, inducing a conformational change that allows actin-myosin interaction and muscle contraction. TNNC2 is essential for excitation-contraction coupling in fast skeletal muscle.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Nemaline myopathy 4 (NEM4) | Missense mutations in TNNC2 disrupt calcium binding or troponin complex assembly, impairing muscle contraction and leading to nemaline rod formation. | ClinVar, OMIM |
| Distal arthrogryposis type 2B (DA2B) | Dominant mutations alter calcium sensitivity, causing abnormal muscle contracture and joint deformities. | ClinVar, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skeletal muscle (fast fibers) | >1000 | High |
| Heart | <10 | Not detected |
| Liver | <1 | Not detected |
| Brain | <1 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| LHCN-M2 (skeletal muscle myoblasts) | 150 | Differentiated myotubes show higher expression |
| RD (rhabdomyosarcoma) | 5 | Low expression in cancer cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.363C>A (p.Asp121Glu) | Missense | <0.01% | Reduced calcium binding affinity; associated with nemaline myopathy |
| c.238G>A (p.Glu80Lys) | Missense | <0.01% | Alters troponin C-troponin I interaction; pathogenic in distal arthrogryposis |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations (e.g., nonsense or frameshift) are rare and likely cause haploinsufficiency, leading to muscle weakness.
Gain of Function (GOF)
Gain-of-function mutations (e.g., p.Asp121Glu) increase calcium sensitivity, resulting in hypercontractility and arthrogryposis.
Dominant Negative (DN)
Dominant-negative mutations (e.g., p.Glu80Lys) disrupt troponin complex assembly, impairing normal muscle relaxation.
View complete mutation data：
Gene Ontology (GO)
| • calcium ion binding | • troponin complex |
| • muscle contraction | • regulation of muscle contraction |
| • calcium-dependent ATPase activity |
Pathways
• Cardiac and skeletal muscle contraction (KEGG: hsa04260)
• Calcium signaling pathway (KEGG: hsa04020)
• Troponin complex assembly
Protein Summary
Troponin C2 (fast skeletal) is a 161-amino acid protein with four EF-hand calcium-binding domains. It binds up to four calcium ions per molecule, with two high-affinity sites (Ca2+/Mg2+ sites) and two low-affinity regulatory sites. Upon calcium binding, it undergoes a conformational change that moves tropomyosin away from actin, enabling myosin cross-bridge formation. The protein is exclusively expressed in fast-twitch skeletal muscle fibers.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| TNNC2 Knockout HEK293 Cell Line | EDJ-KQ1633 | Human | 7125 | Details Get a Quote |
| TNNC2 Knockout HeLa Cell Line | EDJ-KQ54676 | Human | 7125 | Details Get a Quote |
| TNNC2 Knockout A-549 Cell Line | EDJ-KQ63159 | Human | 7125 | Details Get a Quote |
| TNNC2 Knockout HCT 116 Cell Line | EDJ-KQ71632 | Human | 7125 | Details Get a Quote |
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