CWC27 is part of the spliceosome, the ribonucleoprotein machinery that removes introns from pre-mRNA, and it plays a role in pre-mRNA splicing. As a component of the minor spliceosome, it is involved in the splicing of U12-type introns. NCBI Gene annotation places the protein in the nucleoplasm, as part of the U2-type precatalytic spliceosome and the catalytic step 2 spliceosome.

UniProt classifies CWC27 within the cyclophilin-type peptidylprolyl isomerase (PPIase) family. Unlike many family members, it is described as a probable inactive PPIase with no peptidyl-prolyl cis-trans isomerase activity, although NCBI Gene lists that activity as predicted. The CWC27 protein is annotated as localising to the nucleus. Orthologues are present in mouse and rat, both designated Cwc27.

HGNC places the CWC27 gene in several groups: cyclophilin peptidylprolyl isomerases, NTC associated proteins, and the spliceosomal Bact, C and P complexes. These groupings reflect its association with the spliceosome at successive stages of the splicing cycle. The name CWC27 refers to the yeast homologue, and earlier HGNC names include serologically defined colon cancer antigen 10 and CWC27 spliceosome-associated protein homolog. Researchers studying CWC27 antibody or CWC27 ELISA kit reagents will encounter these older aliases, including SDCCAG10, in the literature.