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Troponin C is a protein which is part of the troponin complex. It contains four calcium-binding EF hands, although different isoforms may have fewer than four functional calcium-binding subdomains. It is a component of thin filaments, along with actin and tropomyosin. It contains an N lobe and a C lobe. The C lobe serves a structural purpose and binds to the N domain of troponin I (TnI). The C lobe can bind either Ca2+ or Mg2+. The N lobe, which binds only Ca2+, is the regulatory lobe and binds to the C domain of troponin I after calcium binding.
Isoforms
| Troponin C, slow skeletal and cardiac muscles | |||||||
|---|---|---|---|---|---|---|---|
| Identifiers | |||||||
| Symbol | TNNC1 | ||||||
| HGNC | 11943 | ||||||
| OMIM | 191040 | ||||||
| RefSeq | NM_003280 | ||||||
| UniProt | P63316 | ||||||
| Other data | |||||||
| Locus | Chr. 3 p21.1 | ||||||
| |||||||
| Troponin C, skeletal muscle | |||||||
|---|---|---|---|---|---|---|---|
| Identifiers | |||||||
| Symbol | TNNC2 | ||||||
| HGNC | 11944 | ||||||
| OMIM | 191039 | ||||||
| RefSeq | NP_003270.1 | ||||||
| UniProt | P02585 | ||||||
| Other data | |||||||
| Locus | Chr. 20 q13.12 | ||||||
| |||||||
The tissue specific subtypes are:
- Slow troponin C, TNNC1 (3p21.1 Online Mendelian Inheritance in Man (OMIM): 191040)
- Fast troponin C, TNNC2 (20q12-q13.11, Online Mendelian Inheritance in Man (OMIM): 191039)
Mutations
Point mutations can occur in troponin C inducing alterations to Ca2+ and Mg2+ binding and protein structure,[1] leading to abnormalities in muscle contraction.[2][3] In cardiac muscle, they are related to dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM).
These known point mutations are:
- A8V
- D145E
- A31S
- C84Y
- E134D
- Y5H
- I148V
See also
References
- ^ Kalyva A, Parthenakis FI, Marketou ME, Kontaraki JE, Vardas PE (April 2014). "Biochemical characterisation of Troponin C mutations causing hypertrophic and dilated cardiomyopathies". Journal of Muscle Research and Cell Motility. 35 (2): 161–78. doi:10.1007/s10974-014-9382-0. PMID 24744096. S2CID 1726747.
- ^ Cheng Y, Regnier M (July 2016). "Cardiac troponin structure-function and the influence of hypertrophic cardiomyopathy associated mutations on modulation of contractility". Archives of Biochemistry and Biophysics. Special Issue: Myofilament Modulation of Contraction. 601: 11–21. doi:10.1016/j.abb.2016.02.004. PMC 4899195. PMID 26851561.
- ^ Pinto JR, Parvatiyar MS, Jones MA, Liang J, Ackerman MJ, Potter JD (July 2009). "A functional and structural study of troponin C mutations related to hypertrophic cardiomyopathy". The Journal of Biological Chemistry. 284 (28): 19090–100. doi:10.1074/jbc.M109.007021. PMC 2707221. PMID 19439414.
External links
- Troponin+C at the US National Library of Medicine Medical Subject Headings (MeSH)