Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
Telomeres are the termini of linear chromosomes. They are composed of DNA and DNA-binding proteins critical for maintaining chromosome integrity and cellular function. Telomere binding proteins regulate the structure and function of telomeres through the formation of different complexes with telomeric DNA. Double- and single-stranded telomeric DNA binding protein complexes have shared and unique functions that regulate telomere homeostasis. Recent studies have shown that telomerase interacts with several telomere-binding protein complexes including shelterin, CST, DNA-dependent protein kinase (DNA-PK) and MRN. The present review describes the recognised telomere-binding protein complexes, sub-complex exchanges and inter-complex molecular interactions. It also discusses the evidence suggesting that telomerase reverse transcriptase (TERT) switches between different complexes. Studies of the telomere protein inter-complex interactions and the switching of components between complexes provide insight into their fundamental roles of programming telomere length and configuration, and thus cell proliferative potential.