The bipartite CS domain, which was named after CHORD-containing proteins and SGT1 [1], is a ~100-residue protein-protein interaction module. It is only present in eukaryota (alveolata, fungi, metazoa, and plant divisions). The CS domain can be found in stand-alone form, as well as fused with other domains, such as CHORD, SGS (see <PDOC51048>), TPR (see <PDOC50005>), cytochrome b5 (see <PDOC00170>) or b5 reductase, in multidomain proteins [2].

The CS domain has a compact antiparallel β-sandwich fold consisting of seven β-strands (see <PDB:1EJF>) [2,3].

Some proteins known to contain a CS domain are listed below [2]:

• 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 β-1-binding protein 2 (melusin).

The profile we developed covers the entire CS domain.