This domain is found at the N-terminal end of Protein SHQ1 homolog from humans and similar eukaryotic proteins. SHQ1 is a factor required for the biogenesis and assembly of H/ACA small nucleolar ribonucleoparticle (snoRNP), which are essential for ribosomal RNA and telomerase RNA processing and metabolism. This protein contains two domains: an N-terminal CS (named after CHORD-containing proteins and SGT1) or HSP20-like domain (represented by this entry), and a C-terminal region called the Shq1 domain (Pfam:PF04925). The CS domain folds into a compact anti-parallel beta-sandwich made of two beta-sheets with four and three beta-strands, respectively, and a short alpha-helix [1-3].

1: The box H/ACA snoRNP assembly factor Shq1p is a chaperone protein homologous to Hsp90 cochaperones that binds to the Cbf5p enzyme. Godin KS, Walbott H, Leulliot N, van Tilbeurgh H, Varani G; J Mol Biol. 2009;390:231-244. PMID:19426738

2: Structure and interactions of the CS domain of human H/ACA RNP assembly protein Shq1. Singh M, Wang Z, Cascio D, Feigon J; J Mol Biol. 2015;427:807-823. PMID:25553844

3: Structure and functional studies of the CS domain of the essential H/ACA ribonucleoparticle assembly protein SHQ1. Singh M, Gonzales FA, Cascio D, Heckmann N, Chanfreau G, Feigon J; J Biol Chem. 2009;284:1906-1916. PMID:19019820