Troponin C is a part of the troponin

Troponin

400px|thumb|right|alt = Colored dice with checkered background|Ribbon representation of the human cardiac troponin core complex in the calcium-saturated form...

 complex. It contains four calcium-binding EF hand

EF hand

The EF hand is a helix-loop-helix structural domain found in a large family of calcium-binding proteins. The EF-hand motif contains a helix-loop-helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca2+ ions are coordinated by ligands within the loop...

s. It is a component of thin filaments (along with actin

Actin

Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...

 and tropomyosin

Tropomyosin

Tropomyosin is an actin-binding protein that regulates actin mechanics. It is important, among other things, for muscle contraction. Tropomyosin, along with the troponin complex, associate with actin in muscle fibers and regulate muscle contraction by regulating the binding of myosin...

). It contains an N lobe and a C lobe. The C lobe serves a structural purpose and binds to the N domain of 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 TnI after calcium binding.

The tissue specific subtypes are:

• Slow troponin C, TNNC1 (3p21.3-p14.3)
• Fast troponin C, TNNC2
  TNNC2
  Troponin C, skeletal muscle is a protein that in humans is encoded by the TNNC2 gene.-Further reading:...
  
  (20q12-q13.11)