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275  structures 1470  species 0  interactions 62264  sequences 1584  architectures

Family: CH (PF00307)

Summary: Calponin homology (CH) domain

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Calponin homology domain Edit Wikipedia article

Calponin homology (CH) domain
Solution structure of calponin homology domain of IQGAP1[1]

Calponin homology domain (or CH domain) is a family of actin binding domains found in both cytoskeletal proteins and signal transduction proteins.[2] The domain is about 100 amino acids in length and is composed of four alpha helices.[3] It comprises the following groups of actin-binding domains:

A comprehensive review of proteins containing this type of actin-binding domains is given in.[4]

The CH domain is involved in actin binding in some members of the family. However, in calponins there is evidence that the CH domain is not involved in its actin binding activity.[5] Most proteins have two copies of the CH domain, however some proteins such as calponin and the human vav proto-oncogene (P15498) have only a single copy. The structure of an example CH domain has been determined using X-ray crystallography.[6]


Human genes encoding calponin homology domain-containing proteins include:


  1. ^ PDB: 2RR8​; Umemoto R, Nishida N, Ogino S, Shimada I (September 2010). "NMR structure of the calponin homology domain of human IQGAP1 and its implications for the actin recognition mode". J. Biomol. NMR. 48 (1): 59–64. doi:10.1007/s10858-010-9434-8. PMID 20644981.
  2. ^ Saraste M, Castresana J (1995). "Does Vav bind to F-actin through a CH domain?". FEBS Lett. 374 (2): 149–151. doi:10.1016/0014-5793(95)01098-Y. PMID 7589522.
  3. ^ Korenbaum, E.; Rivero, F. (Sep 2002). "Calponin homology domains at a glance". J Cell Sci. 115 (Pt 18): 3543–5. CiteSeerX doi:10.1242/jcs.00003. PMID 12186940.
  4. ^ Hartwig JH (1995). "Actin-binding proteins. 1: Spectrin super family". Protein Prof. 2 (7): 703–800. PMID 7584474.
  5. ^ Gimona M, Mital R (1998). "The single CH domain of calponin is neither sufficient nor necessary for F-actin binding". J. Cell Sci. 111: 1813–1821. PMID 9625744.
  6. ^ Saraste M, Carugo KD, Banuelos S (1997). "Crystal structure of a calponin homology domain". Nat. Struct. Biol. 4 (3): 175–179. doi:10.1038/nsb0397-175. PMID 9164454.
This article incorporates text from the public domain Pfam and InterPro: IPR001715

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Calponin homology (CH) domain Provide feedback

The CH domain is found in both cytoskeletal proteins and signal transduction proteins [1]. The CH domain is involved in actin binding in some members of the family. However in calponins there is evidence that the CH domain is not involved in its actin binding activity [4]. Most member proteins have from two to four copies of the CH domain, however some proteins such as calponin and P15498 have only a single copy.

Literature references

  1. Castresana J, Saraste M; , FEBS Lett 1995;374:149-151.: Does Vav bind to F-actin through a CH domain? PUBMED:7589522 EPMC:7589522

  2. Carugo KD, Banuelos S, Saraste M; , Nat Struct Biol 1997;4:175-179.: Crystal structure of a calponin homology domain. PUBMED:9164454 EPMC:9164454

  3. Stradal T, Kranewitter W, Winder SJ, Gimona M; , FEBS Lett 1998;431:134-137.: CH domains revisited. PUBMED:9708889 EPMC:9708889

  4. Gimona M, Mital R; , J Cell Sci 1998;111:1813-1821.: The single CH domain of calponin is neither sufficient nor necessary for F-actin binding. PUBMED:9625744 EPMC:9625744

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001715

A number of actin-binding proteins, including spectrin, alpha-actinin and fimbrin, contain a 250 amino acid stretch called the actin binding domain (ABD). The ABD has probably arisen from duplication of a domain which is also found in a single copy in a number of other proteins like calponin or the vav proto-oncogene and has been called calponin homology (CH) domain [ PUBMED:9708889 , PUBMED:9887274 ].

A detailed analysis of The CH domain-containing proteins has shown that they can be divided in three groups [ PUBMED:9708889 ]:

  • The fimbrin family of monomeric actin cross-linking molecules containing two ABDs
  • Dimeric cross-linking proteins (alpha-actinin, beta-spectrin, filamin, etc.) and monomeric F-actin binding proteins (dystrophin, utrophin) each containing one ABD
  • Proteins containing only a single amino terminal CH domain.

Each single ABD, comprising two CH domains, is able to bind one actin monomer in the filament. The N-terminal CH domain has the intrinsic ability to bind actin, albeit with lower affinity than the complete ABD, whereas the C-terminal CH bind actin extremely weakly or not at all. Nevertheless both CH domains are required for a fully functional ABD; the C-terminal CH domain contributing to the overall stability of the complete ABD through inter-domain helix-helix interactions [ PUBMED:9708889 ]. Some of the proteins containing a single CH domain also bind to actin, although this has not been shown to be via the single CH domain alone [ PUBMED:9887274 ]. In addition, the CH domain occurs also in a number of proteins not known to bind actin, a notable example being the vav protooncogene.

The resolution of the 3D structure of various CH domains has shown that the conserved core consist of four major alpha-helices [ PUBMED:9887274 ].

Proteins containing a calponin domain include:

  • Calponin, which is involved in the regulation of contractility and organisation of the actin cytoskeleton in smooth muscle cells [ PUBMED:11839310 ].
  • Beta-spectrin, a major component of a submembrane cytoskeletal network connecting actin filaments to integral plasma membrane proteins [ PUBMED:17121810 ].
  • The actin-cross-linking domain of the fimbrin/plastin family of actin filament bundling or cross-linking proteins [ PUBMED:9302997 ].
  • Utrophin,a close homologue of dystrophin [ PUBMED:9887274 ].
  • Dystrophin, the protein found to be defective in Duchenne muscular dystrophy; this protein contains a tandem repeat of two CH domains [ PUBMED:10801490 ].
  • Actin-binding domain of plectin, a large and widely expressed cytolinker protein [ PUBMED:15128297 ].
  • The N-terminal microtubule-binding domain of microtubule-associated protein eb1 (end-binding protein), a member of a conserved family of proteins that localise to the plus-ends of microtubules [ PUBMED:12857735 ].
  • Ras GTPase-activating-like protein rng2, an IQGAP protein that is essential for the assembly of an actomyosin ring during cytokinesis [ PUBMED:15272162 ].
  • Transgelin, which suppresses androgen receptor transactivation [ PUBMED:17082327 ].

Gene Ontology

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Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan CH (CL0188), which has the following description:

The calponin homology (CH) domain is found in a variety of contexts, ranging from proteins involved in signalling pathways to cytoskeletal proteins. They seem to have diverse cellular functions, which are thought to include actin binding, involvement in the MAP kinase signalling pathway, and regulation of GEF activity in Rho family GTPase pathways. Structurally, they are organised into three layers, with two parallel alpha helices in the core being sandwiched between another two helices, one on each side [1].

The clan contains the following 7 members:



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Seed source: Prosite
Previous IDs: actinin-binding;
Type: Domain
Sequence Ontology: SO:0000417
Author: Finn RD
Number in seed: 121
Number in full: 62264
Average length of the domain: 107.60 aa
Average identity of full alignment: 19 %
Average coverage of the sequence by the domain: 11.18 %

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HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 26.0 22.1
Trusted cut-off 26.0 22.1
Noise cut-off 25.9 22.0
Model length: 109
Family (HMM) version: 33
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the CH domain has been found. There are 275 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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