Calponin
Calponin is a calcium binding protein. Calponin tonically inhibits the ATPase activity of myosin in smooth muscle. Phosphorylation of calponin by a protein kinase, which is dependent upon calcium binding to calmodulin, releases the calponin's inhibition of the smooth muscle ATPase.
Calponin Homology Domain | |||||||||
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CH domain from H.Sapiends Calponin 1. PDB 1wyp | |||||||||
Identifiers | |||||||||
Symbol | CH | ||||||||
Pfam | PF00307 | ||||||||
Pfam clan | CL0188 | ||||||||
InterPro | IPR001715 | ||||||||
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calponin 1, basic, smooth muscle | |
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Solution structure of the CH domain of human Calponin 1. Rainbow colored cartoon (N-terminus = blue, C-terminus = red).[1] | |
Identifiers | |
Symbol | CNN1 |
NCBI gene | 1264 |
HGNC | 2155 |
OMIM | 600806 |
PDB | 1WYP |
RefSeq | NM_001299 |
UniProt | P51911 |
Other data | |
Locus | Chr. 19 p13.2-13.1 |
calponin 2 | |
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Identifiers | |
Symbol | CNN2 |
NCBI gene | 1265 |
HGNC | 2156 |
OMIM | 602373 |
RefSeq | NM_004368 |
UniProt | Q99439 |
Other data | |
Locus | Chr. 21 q11.1 |
calponin 3, acidic | |
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Identifiers | |
Symbol | CNN3 |
NCBI gene | 1266 |
HGNC | 2157 |
OMIM | 602374 |
RefSeq | NM_001839 |
UniProt | Q6FHA7 |
Other data | |
Locus | Chr. 1 p22-p21 |
Structure and function
Calponin is mainly made up of α-helices with hydrogen bond turns. It is a binding protein and is made up of three domains. These domains in order of appearance are Calponin Homology (CH), regulatory domain (RD), and Click-23, domain that contains the calponin repeats. At the CH domain calponin binds to α-actin and filamin and binds to actin within the RD domain. Calmodulin, when activated by calcium may bind weakly to the CH domain and inhibit calponin binding with α-actin.[2] Calponin is responsible for binding many actin binding proteins, phospholipids, and regulates the actin/myosin interaction. Calponin is also thought to negatively affect the bone making process due to being expressed in high amounts in osteoblasts.[3]
References
- PDB: 1WYP; Tomizawa T, Kigawa T, Koshiba S, Inoue M, Yokoyama S. "RCSB PDB - 1WYP Structure Summary". RCSB Protein Data Bank. doi:10.2210/pdb1wyp/pdb. Cite journal requires
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(help) - Ferjani, I; Fattoum, A; Manai, M; Benyamin, Y; Roustan, C; Maciver, SK (September 2010). "Two distinct regions of calponin share common binding sites on actin resulting in different modes of calponin-actin interaction". Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics. 1804 (9): 1760–7. doi:10.1016/j.bbapap.2010.05.012. PMID 20595006.
- Maciver S. "The Calponin Family". Department of Biomedical Sciences, University of Edinburgh. Retrieved 2011-04-25.