[Frontiers in Bioscience 16, 187-207, January 1, 2011]

Telomere protein complexes and interactions with telomerase in telomere maintenance

Alexander Ruvantha Pinto 1, He Li1, Craig Nicholls1, Jun-Ping Liu 1

1Molecular Signaling Laboratory, Department of Immunology, Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Telomere shortening and lengthening
4. Telomere binding protein complexes
4.1. Telomerase complexes
4.1.1. TERT sub-complexes
4.1.2. TER sub-complexes
4.2. The shelterin complex
4.3. The CST complex
4.4. The RAP1-TRF2 complex
4.5. The MRN complex
4.6. The DNA-PK complex
4.7. Other telomere protein complexes
5. Interactions between telomerase and telomere binding complexes
5.1. Interactions between telomerase and shelterin complexes
5.2. Interactions between telomerase and CST complexes
5.3. Interactions between telomerase and DNA-PK complexes
5.4. Interactions between telomerase and MRN complexes
6. Perspectives
7. Acknowledgements
8. References

1. ABSTRACT

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.