Component of the telomerase ribonucleoprotein (RNP) complex that is essential for the replication of chromosome termini. Is a component of the double-stranded telomeric DNA-binding TRF1 complex that is involved in the regulation of telomere length by cis-inhibition of telomerase. Also acts as a single-stranded telomeric DNA-binding protein and thus may act as a downstream effector of the TRF1 complex and may transduce information about telomere maintenance and/or length to the telomere terminus. Binds to at least two telomeric single-stranded 5'-TTAGGG-3' repeats (G-strand). Its activity is TERT dependent but it does not increase TERT activity (By similarity). Homodimer or homooligomer. Component of the telomerase ribonucleoprotein complex. Binds single-stranded telomeric DNA as a monomer (By similarity). Found in a complex with TERF1, TINF2 and TNKS1. Interacts with TNKS1 (By similarity). Colocalizes with telomeric DNA. Belongs to the telombin family.