3tix | pdb_00003tix
Crystal structure of the Chp1-Tas3 complex core
Structural highlights
Function[SMT3_YEAST] Not known; suppressor of MIF2 mutations. [CHP1_SCHPO] Component of the kinetochore which plays a role in stabilizing microtubules and so allowing accurate chromosome segregation. Has a role in the RNA interference (RNAi) pathway which is important for heterochromatin formation and accurate chromosome segregation. A member of the RNA-induced transcriptional silencing (RITS) complex which is involved in the biosynthesis of dsRNA from primer siRNAs provided by the RNA-directed RNA polymerase (RDRC) complex.[1] [2] [3] [4] Publication Abstract from PubMedRNA interference (RNAi) is critical for the assembly of heterochromatin at Schizosaccharomyces pombe centromeres. Central to this process is the RNA-induced initiation of transcriptional gene silencing (RITS) complex, which physically anchors small noncoding RNAs to chromatin. RITS includes Ago1, the chromodomain protein Chp1, and Tas3, which forms a bridge between Chp1 and Ago1. Chp1 is a large protein with no recognizable domains, apart from its chromodomain. Here we describe how the structured C-terminal half of Chp1 binds the Tas3 N-terminal domain, revealing the tight association of Chp1 and Tas3. The structure also shows a PIN domain at the C-terminal tip of Chp1 that controls subtelomeric transcripts through a post-transcriptional mechanism. We suggest that the Chp1-Tas3 complex provides a solid and versatile platform to recruit both RNAi-dependent and RNAi-independent gene-silencing pathways for locus-specific regulation of heterochromatin. 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 Nov 13;18(12):1351-7. doi: 10.1038/nsmb.2151. PMID:22081013[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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