Telomerase maintains chromosome ends from humans to yeasts. Recruitment of yeast telomerase to telomeres occurs through its Ku and Est1 subunits via independent interactions with telomerase RNA (TLC1) and telomeric proteins Sir4 and Cdc13, respectively. However, the structures of the molecules comprising these telomerase-recruiting pathways remain unknown. Here, we report crystal structures of the Ku heterodimer and Est1 complexed with their key binding partners. Two major findings are as follows: (1) Ku specifically binds to telomerase RNA in a distinct, yet related, manner to how it binds DNA; and (2) Est1 employs two separate pockets to bind distinct motifs of Cdc13. The N-terminal Cdc13-binding site of Est1 cooperates with the TLC1-Ku-Sir4 pathway for telomerase recruitment, whereas the C-terminal interface is dispensable for binding Est1 in vitro yet is nevertheless essential for telomere maintenance in vivo. Overall, our results integrate previous models and provide fundamentally valuable structural information regarding telomere biology.
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http://dx.doi.org/10.1016/j.cell.2017.12.008 | DOI Listing |
Life Sci
January 2025
Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, China. Electronic address:
Aims: High telomerase activity has been detected in over 85 % of tumors, with the activation of hTERT being the most crucial mechanism for re-establishing telomerase activity. Activation of hTERT maintains telomere length in cells, enabling cancer cells to proliferate indefinitely. Nevertheless, the specific mechanism of telomerase activation in non-small cell lung cancer (NSCLC) remains unclear, and post-transcriptional regulation of hTERT could be a potential activation mechanism.
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December 2024
Laboratory of Chromosome Dynamics and Gene Regulation, Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
Single-molecule tracking provides direct real-time measurements of protein dynamics in live cells with high spatiotemporal resolution. In the last decade, this method has been adopted by several labs to understand the dynamics of DNA replication, transcription, telomerase, chromatin remodeling, etc. in a variety of model systems (bacteria, yeast S.
View Article and Find Full Text PDFCold Spring Harb Perspect Biol
December 2024
Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, LBMCE, F-75005 Paris, France
, a model organism in telomere biology, has been instrumental in pioneering a comprehensive understanding of the molecular processes that occur in the absence of telomerase across eukaryotes. This exploration spans investigations into telomere dynamics, intracellular signaling cascades, and organelle-mediated responses, elucidating their impact on proliferative capacity, genome stability, and cellular variability. Through the lens of budding yeast, numerous sources of cellular heterogeneity have been identified, dissected, and modeled, shedding light on the risks associated with telomeric state transitions, including the evasion of senescence.
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September 2024
GReD Institute, CNRS UMR6293, INSERM U1103, Faculty of Medicine, University Clermont-Auvergne, 28 Place Henri Dunant, BP 38, 63001 Clermont-Ferrand Cedex, France.
Telomeres, the ends of eukaryotic linear chromosomes, are composed of repeated DNA sequences and specialized proteins, with the conserved telomeric Cdc13/CTC1-Stn1-Ten1 (CST) complex providing chromosome stability via telomere end protection and the regulation of telomerase accessibility. In this study, , coding for a SUMO E3 ligase, and (a SUMO target for Siz1 and Siz2) were isolated as extragenic suppressors of CST temperature-sensitive mutants. -, - and - mutants were isolated next due to being sensitive to intracellular Siz1 dosage.
View Article and Find Full Text PDFInt J Biol Macromol
November 2024
State Key Laboratory of Tree Genetics and Breeding, National Engineering Research Center of Tree Breeding and Ecological Restoration, Beijing Forestry University, Beijing 100083, China; The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China. Electronic address:
The heat shock protein 90 (HSP90) family members are not only widely involved in animal cellular immune response and signal transduction pathway regulation, but also play an important role in plant development and environmental stress response. Here,we identified a HSP90 family member in Ginkgo biloba, designated as GbHSP90, which performs a dual functional role to regulate telomere stability. GbHSP90 was screened by a yeast one-hybrid library using the Ginkgo biloba telomeric DNA (TTTAGGG).
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