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Crystal structure of Poz1, Tpz1 and Rap1
Structural highlights
FunctionPOZ1_SCHPO Telomeric DNA-binding protein that negatively regulates telomerase and telomere length.[1] Publication Abstract from PubMedTelomeric shelterin complex caps chromosome ends and plays a crucial role in telomere maintenance and protection. In the fission yeast Schizosaccharomyces pombe, shelterin is composed of telomeric single- and double-stranded DNA-binding protein subcomplexes Pot1-Tpz1 and Taz1-Rap1, which are bridged by their interacting protein Poz1. However, the structure of Poz1 and how Poz1 functions as an interaction hub in the shelterin complex remain unclear. Here we report the crystal structure of Poz1 in complex with Poz1-binding motifs of Tpz1 and Rap1. The crystal structure shows that Poz1 employs two different binding surfaces to interact with Tpz1 and Rap1. Unexpectedly, the structure also reveals that Poz1 adopts a dimeric conformation. Mutational analyses suggest that proper interactions between Tpz1, Poz1, and Rap1 in the shelterin core complex are required for telomere length homeostasis and heterochromatin structure maintenance at telomeres. Structural resemblance between Poz1 and the TRFH domains of other shelterin proteins in fission yeast and humans suggests a model for the evolution of shelterin proteins. Structure of the fission yeast S. pombe telomeric Tpz1-Poz1-Rap1 complex.,Xue J, Chen H, Wu J, Takeuchi M, Inoue H, Liu Y, Sun H, Chen Y, Kanoh J, Lei M Cell Res. 2017 Dec;27(12):1503-1520. doi: 10.1038/cr.2017.145. Epub 2017 Nov 21. PMID:29160296[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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