Troponins
| Parent |
| Microfilament |
| Subordinate |
|
Cardiac Troponin. Red Skeletal Troponin. White Skeletal Troponin |
| Gene Ontology |
|---|
| QuickGO |
The troponins are three protein complexes that occur in the skeletal and heart muscles of the chordates . They each have three subunits, with subunit C being responsible for binding calcium , T for binding tropomyosin and I for binding actin (I for inhibitory ). Together with myosin and actin , these protein complexes form the mobile (contractile) part of the muscles .
Biological function
If calcium ions bind to troponin C, the complex changes its conformation and thus releases the myosin binding sites, which enables contraction. Troponin C is largely homologous with calmodulin , which is mainly responsible for binding calcium ions in the cells of the smooth muscles.
structure
There are three troponins, which are made up of a total of eight different subunits, whereby the two known TN-C subunits differ only slightly:
- Cardiac troponin , from cTnT, cTnI, TN-C
- Skeletal troponin of white muscles, from fTnT, fTnI, TN-C2
- Red muscle skeletal troponin , sTnT, sTnI, TN-C
pathology
Changes in the genes that code for one of the troponin subunits can lead to hereditary diseases:
- cTnT:
- Hypertrophic Cardiomyopathy (CMH2)
- Dilated cardiomyopathy (CMD1D)
- Restrictive Cardiomyopathy (RCM3)
- cTnI:
- Hypertrophic Cardiomyopathy (CMH7)
- Restrictive cardiomyopathy (RCM1)
- Dilated cardiomyopathy (CMD2A)
- TN-C:
- Dilated cardiomyopathy (CMD1Z)
- Hypertrophic Cardiomyopathy (CMH13)
- fTnT, fTnI: Arthrogryposis multiplex congenita (DA2B, AMCD2B)
- sTnT: Nemaline Myopathy -5 (NEM5)
literature
- Jeremy M. Berg, John L. Tymoczko, Lubert Stryer : Biochemistry. 6 edition, Spektrum Akademischer Verlag, Heidelberg 2007. ISBN 978-3-8274-1800-5 .
- Donald Voet, Judith G. Voet: Biochemistry. 3rd edition, John Wiley & Sons, New York 2004. ISBN 0-471-19350-X .
- Bruce Alberts , Alexander Johnson, Peter Walter, Julian Lewis, Martin Raff, Keith Roberts: Molecular Biology of the Cell , 5th Edition, Taylor & Francis 2007, ISBN 978-0815341062 .