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calponin 1, basic, smooth muscle
calponin 1, basic, smooth muscle
	Solution structure of the CH domain of human Calponin 1. Rainbow colored cartoon (N-terminus = blue, C-terminus = red).
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
Structures
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Structures	Swiss-model
Domains	InterPro

Available protein structures:
Pfam	structures / ECOD
PDB	RCSB PDB; PDBe; PDBj
PDBsum	structure summary

Calponin Homology Domain
Calponin Homology Domain
	CH domain from H.Sapiends Calponin 1. PDB 1wyp
Identifiers
Symbol	CH
Pfam	PF00307
Pfam clan	CL0188
InterPro	IPR001715
Pfam
Available protein structures:
Pfam	structures / ECOD
PDB	RCSB PDB; PDBe; PDBj
PDBsum	structure summary

calponin 2

Identifiers

Symbol

Other data

Chr. 19 p13.3

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Structures	Swiss-model
Domains	InterPro

calponin 3, acidic

Identifiers

Symbol

Other data

Chr. 1 p22-p21

Search for
Structures	Swiss-model
Domains	InterPro

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.

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}}: Cite journal requires |journal= (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.