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25  structures 683  species 6  interactions 4522  sequences 165  architectures

Family: CS (PF04969)

Summary: CS domain

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CS domain Provide feedback

The CS and CHORD (PF04968) are fused into a single polypeptide chain in metazoans but are found in separate proteins in plants; this is thought to be indicative of an interaction between CS and CHORD [1]. It has been suggested that the CS domain is a binding module for HSP90, implying that CS domain-containing proteins are involved in recruiting heat shock proteins to multiprotein assemblies [2]. Two CS domains are found at the N-terminus of Ubiquitin carboxyl-terminal hydrolase 19 (USP19) (O94966), these domains may play a role in the interaction of USP19 with cellular inhibitor of apoptosis 2 [3].

Literature references

  1. Shirasu K, Lahaye T, Tan MW, Zhou F, Azevedo C, Schulze-Lefert P; , Cell 1999;99:355-366.: A novel class of eukaryotic zinc-binding proteins is required for disease resistance signaling in barley and development in C. elegans. PUBMED:10571178 EPMC:10571178

  2. Lee YT, Jacob J, Michowski W, Nowotny M, Kuznicki J, Chazin WJ; , J Biol Chem 2004;279:16511-16517.: Human Sgt1 binds HSP90 through the CHORD-Sgt1 domain and not the tetratricopeptide repeat domain. PUBMED:14761955 EPMC:14761955

  3. Mei Y, Hahn AA, Hu S, Yang X;, J Biol Chem. 2011;286:35380-35387.: The USP19 deubiquitinase regulates the stability of c-IAP1 and c-IAP2. PUBMED:21849505 EPMC:21849505

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR007052

The bipartite CS domain, which was named after CHORD-containing proteins and SGT1 [PUBMED:10571178], is a ~100-residue protein-protein interaction module. The CS domain can be found in stand-alone form, as well as fused with other domains, such as CHORD, SGS (see PROSITEDOC), TPR (see PROSITEDOC), cytochrome b5 (see PROSITEDOC) or b5 reductase, in multidomain proteins [PUBMED:12372593].

The CS domain has a compact antiparallel beta-sandwich fold consisting of seven beta-strands [PUBMED:12372593, PUBMED:14761955].

Some proteins known to contain a CS domain are listed below [PUBMED:12372593]:

  • Eukaryotic proteins of the SGT1 family.
  • Eukaryotic Rar1, related to pathogenic resistance in plants, and to development in animals.
  • Eukaryotic nuclear movement protein nudC.
  • Eukaryotic proteins of the p23/wos2 family, which act as co-chaperone.
  • Animal b5+b5R flavo-hemo cytochrome NAD(P)H oxydoreductase type B.
  • Mammalian integrin beta-1-binding protein 2 (melusin).

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 HSP20 (CL0190), which has the following description:

The small heat shock proteins (sHSPs) prevent protein aggregation during heat shock and oppose regulated cell death. A conserved arginine residue in the HSP20/alpha-crystallin domain (Pfam:PF00011) has in fact been implicated in the development of cataracts and myopathies [1]. The CS family (Pfam:PF04969) includes proteins that are known to bind HSP90 [2], as well as p23 (Swiss:Q15185), which is an HSP90 co-chaperone [3].

The clan contains the following 4 members:



We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

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HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

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Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Pfam-B_1217 (release 7.0)
Previous IDs: none
Type: Domain
Author: Finn RD, Fenech M, Eberhardt R
Number in seed: 76
Number in full: 4522
Average length of the domain: 77.10 aa
Average identity of full alignment: 19 %
Average coverage of the sequence by the domain: 23.25 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.3 10.0
Trusted cut-off 21.3 10.0
Noise cut-off 21.2 9.9
Model length: 79
Family (HMM) version: 12
Download: download the raw HMM for this family

Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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There are 6 interactions for this family. More...

HSP90 CHORD Siah-Interact_N HATPase_c_3 SGS CS


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 CS domain has been found. There are 25 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 seqence.

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