Structural basis of human telomerase recruitment by TPP1-POT1

Science. 2022 Mar 11;375(6585):1173-1176. doi: 10.1126/science.abn6840. Epub 2022 Feb 24.

Abstract

Telomerase maintains genome stability by extending the 3' telomeric repeats at eukaryotic chromosome ends, thereby counterbalancing progressive loss caused by incomplete genome replication. In mammals, telomerase recruitment to telomeres is mediated by TPP1, which assembles as a heterodimer with POT1. We report structures of DNA-bound telomerase in complex with TPP1 and with TPP1-POT1 at 3.2- and 3.9-angstrom resolution, respectively. Our structures define interactions between telomerase and TPP1-POT1 that are crucial for telomerase recruitment to telomeres. The presence of TPP1-POT1 stabilizes the DNA, revealing an unexpected path by which DNA exits the telomerase active site and a DNA anchor site on telomerase that is important for telomerase processivity. Our findings rationalize extensive prior genetic and biochemical findings and provide a framework for future mechanistic work on telomerase regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Catalytic Domain
  • Cryoelectron Microscopy
  • DNA / chemistry*
  • DNA / metabolism
  • Humans
  • Models, Molecular
  • Protein Binding
  • Protein Conformation
  • Protein Domains
  • Protein Interaction Domains and Motifs
  • Shelterin Complex / chemistry*
  • Shelterin Complex / metabolism
  • Telomerase / chemistry*
  • Telomere / metabolism*
  • Telomere-Binding Proteins / chemistry*
  • Telomere-Binding Proteins / metabolism

Substances

  • ACD protein, human
  • POT1 protein, human
  • Shelterin Complex
  • Telomere-Binding Proteins
  • DNA
  • TERT protein, human
  • Telomerase