Shelterin complex (TRF2 and POT1 components) (Shelterin)

The Shelterin complex is a specialized protein assembly essential for protecting telomeres, the repetitive DNA sequences at the ends of linear chromosomes (de Lange, 2005, Genes & Development). Within this complex, Telomeric repeat-binding factor 2 (TRF2/TERF2) binds to double-stranded telomeric DNA, while Protection of telomeres protein 1 (POT1) binds to the single-stranded 3' overhang (UniProt P54275; UniProt Q9NUX5). Together, they prevent the cell's DNA repair machinery from mistakenly identifying chromosome ends as double-strand breaks, thereby avoiding deleterious chromosomal fusions and senescence (Palm & de Lange, 2008, Annual Review of Genetics). In many cancers, the shelterin complex is exploited or upregulated to maintain telomere integrity despite rapid cell division, making it a significant therapeutic target (Beier et al., 2012, Journal of Cell Science). Pharmacological disruption of TRF2 or POT1 binding to DNA, often via G-quadruplex stabilizers like CX-5461, induces telomere uncapping, which triggers DNA damage signaling and leads to apoptosis or senescence in malignant cells (Xu et al., 2017, Nature Communications). This mechanism of action bypasses the need for gradual telomere shortening, providing a more rapid anti-tumor effect. However, therapeutic challenges include the potential for systemic genomic instability and toxicity in high-turnover healthy tissues (Beier et al., 2012). Research continues into small molecules that specifically target the protein-protein or protein-DNA interfaces within the complex to improve selectivity.

Other names

TelosomeTRF2-POT1-DNA complexTelomeric repeat-binding factor 2Protection of telomeres protein 1TERF2POT1TRF2 and POT1 binding to telomeric DNA

Disruption of telomere capping and induction of DNA damage response