Binds the telomeric double-stranded 5'-TTAGGG-3' repeat and plays a central role in telomere maintenance and protection against end-to-end fusion of chromosomes. In addition to its telomeric DNA-binding role, required to recruit a number of factors and enzymes required for telomere protection, including the shelterin complex, TERF2IP/RAP1 and DCLRE1B/Apollo. Component of the shelterin complex (telosome) that is involved in the regulation of telomere length and protection. Shelterin associates with arrays of double-stranded 5'-TTAGGG-3' repeats added by telomerase and protects chromosome ends; without its protective activity, telomeres are no longer hidden from the DNA damage surveillance and chromosome ends are inappropriately processed by DNA repair pathways. Together with DCLRE1B/Apollo, plays a key role in telomeric loop (T loop) formation by generating 3' single-stranded overhang at the leading end telomeres: T loops have been proposed to protect chromosome ends from degradation and repair. Required both to recruit DCLRE1B/Apollo to telomeres and activate the exonuclease activity of DCLRE1B/Apollo. Preferentially binds to positive supercoiled DNA. Together with DCLRE1B/Apollo, required to control the amount of DNA topoisomerase (TOP1, TOP2A and TOP2B) needed for telomere replication during fork passage and prevent aberrant telomere topology. Recruits TERF2IP/RAP1 to telomeres, thereby participating in to repressing homology-directed repair (HDR), which can affect telomere length. Ubiquitous. Highly expressed in spleen, thymus, prostate, uterus, testis, small intestine, colon and peripheral blood leukocytes. 2 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Molecular Function: DNA-binding transcription factor activity, RNA polymerase II-specific; double-stranded telomeric DNA binding; enzyme binding; G-rich strand telomeric DNA binding; protein binding; protein C-terminus binding; protein homodimerization activity; protein-containing complex binding; telomeric DNA binding
Biological Process: anterograde axonal transport of messenger ribonucleoprotein complex; cell cycle; cellular senescence; negative regulation of beta-galactosidase activity; negative regulation of cellular senescence; negative regulation of exonuclease activity; negative regulation of gene expression; negative regulation of t-circle formation; negative regulation of telomere capping; negative regulation of telomere maintenance; negative regulation of telomere maintenance via recombination; negative regulation of telomere maintenance via semi-conservative replication; negative regulation of telomere maintenance via telomerase; negative regulation of telomere maintenance via telomere lengthening; negative regulation of telomere single strand break repair; negative regulation of telomeric D-loop disassembly; positive regulation of gene expression; positive regulation of nitric-oxide synthase activity; protection from non-homologous end joining at telomere; protein localization to chromosome, telomeric region; regulation of telomere maintenance; regulation of telomere maintenance via telomerase; regulation of transcription by RNA polymerase II; RNA-dependent DNA biosynthetic process; telomere capping; telomere maintenance; telomeric D-loop disassembly; telomeric loop formation