This domain is found at the C-terminal end of Chromo domain- containing protein 1 from Schizosaccharomyces pombe (Chp1) and similar proteins predominantly found in yeast. Chp1 is a component of the RNA-induced initiation of Transcriptional Gene Silencing (RITS) complex, a central player RNA interference (RNAi) pathway which is important for heterochromatin formation and accurate chromosome segregation. This entry represents the PIN domain of Chp1, which shows an alpha-beta fold [1].

1: The Chp1-Tas3 core is a multifunctional platform critical for gene silencing by RITS. Schalch T, Job G, Shanker S, Partridge JF, Joshua-Tor L; Nat Struct Mol Biol. 2011;18:1351-1357. PMID:22081013