Troponin C
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.
The tissue specific subtypes are:
- Slow troponin C, TNNC1 (3p21.3-p14.3, 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, leading to abnormalities in muscle contraction. 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
External links
- Troponin+C at the U.S. National Library of Medicine Medical Subject Headings (MeSH)