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Title: POT1-TPP1 differentially regulates telomerase via POT1 His266 and as a function of single-stranded telomere DNA length

Journal Article · · Proceedings of the National Academy of Sciences of the United States of America

Telomeres cap the ends of linear chromosomes and terminate in a single-stranded DNA (ssDNA) overhang recognized by POT1-TPP1 heterodimers to help regulate telomere length homeostasis. Here hydroxyl radical footprinting coupled with mass spectrometry was employed to probe protein–protein interactions and conformational changes involved in the assembly of telomere ssDNA substrates of differing lengths bound by POT1-TPP1 heterodimers. Our data identified environmental changes surrounding residue histidine 266 of POT1 that were dependent on telomere ssDNA substrate length. We further determined that the chronic lymphocytic leukemia-associated H266L substitution significantly reduced POT1-TPP1 binding to short ssDNA substrates; however, it only moderately impaired the heterodimer binding to long ssDNA substrates containing multiple protein binding sites. Additionally, we identified a telomerase inhibitory role when several native POT1-TPP1 proteins coat physiologically relevant lengths of telomere ssDNA. This POT1-TPP1 complex-mediated inhibition of telomerase is abrogated in the context of the POT1 H266L mutation, which leads to telomere overextension in a malignant cellular environment.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE; National Institutes of Health (NIH); National Cancer Institute Cancer Center Support Grant
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1625040
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America, Vol. 116, Issue 47; ISSN 0027-8424
Publisher:
National Academy of SciencesCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 13 works
Citation information provided by
Web of Science

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