 CH Domain | |
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| Class:Cytoskeletal modulation | |
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Structure:
 The CH domain consists of four main a-helices connected by long loop regions and two or three shorter helices. Three dominant helices form a parallel bundle against which the N-terminal helix packs at a right angle. Two CH domains in tandem pack such that the C-terminal helix of the first domain connects the two domains to create a single compact fold.
Structure reference: Banuelos, S. et al. (1998) Structure 6(11), 1419-1431. PDB: 1BKR.
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Domain binding and function:
The calponin homology (CH) domain is a protein module of approximately 110 amino acids present in cytoskeletal and signal transduction proteins. Two CH domains in tandem form an F-actin binding region at the N-termini of spectrin-like proteins such as dystrophin and alpha-actinin. Such tandem CH domains bind F-actin with 5 - 50 uM affinity and cross-link actin filaments into bundles and networks. CH domains can be subdivided into at least three types. Type 1 and 2 are found together in tandem in cytoskeletal proteins such as dystrophin, spectrin and filamin. Type 3 CH domains are found in proteins that regulate muscle contraction, such as calponin, as well as in signaling proteins such as Vav, ARHGEF6 and IQGAP. Type 3 CH domains may not interact directly with actin, but rather act as regulatory domains or protein-protein interaction scaffolds to modulate the activity of proteins in which they are present.
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Examples of Proteins:
| CH domain protein |
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Binding partner |
| B-spectrin |  |
F-actin |
| Fimbrin | |
F-actin |
| Dystrophin | |
F-actin |
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Referenced in part on Cell Signaling Technology Website, Reference Section on Protein Domains. We gratefully acknowledge the following contributors:
Piers Nash1, Dan Lin3, Kathleen Binns2, Clark Wells2, Rob Ingham2, Terry Kubiseski2, Bernard Liu1, Matt Smith2,3, Ivan Blasutig2,3, Maria Sierra1, Caesar Lim2,3, Michael Arc1, Jim Fawcett2 and Tony Pawson2,3.
1. Ben May Institute for Cancer Research, The University of Chicago, Chicago, Illinois, 60637, USA
2. Program in Molecular Biology and Cancer, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
3. Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
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