Structural highlights
Function
ACD_HUMAN Component of the shelterin complex (telosome) that is involved in the regulation of telomere length and protection. Shelterin associates with arrays of double-stranded TTAGGG 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. Promotes binding of POT1 to single-stranded telomeric DNA. Modulates the inhibitory effects of POT1 on telomere elongation. The ACD-POT1 heterodimer enhances telomere elongation by increasing telomerase processivity. Plays a role in shelterin complex assembly. May play a role in organogenesis.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
Telomeric POT1-TPP1 binding is critical to telomere maintenance and disruption of this complex may lead to cancer. Current data suggests a reduction of intracellular POT1 levels in the absence of TPP1. Here we provide evidence of POT1 plasticity that contributes to its lack of stability in the absence of TPP1 binding. Structural data reveals inter- and intramolecular POT1C domain flexibility in the absence of TPP1. Thermostability and proteolytic resistance assays show that POT1C and the mutant complex POT1C(Q623H)-TPP1(PBD) are less stable than the wild type POT1C-TPP1(PBD), suggesting that TPP1 binding to POT1 stabilizes POT1C and makes it less accessible to proteasomal degradation in the cell. Disruption of the POT1-TPP1 complex such as through cancer-associated mutations leads to a reduction of intracellular POT1, telomere uncapping, and telomere associated DNA damage response (DDR). DDR in turn leads to senescence or genomic instability and oncogenesis.
POT1-TPP1 binding stabilizes POT1, promoting efficient telomere maintenance.,Aramburu T, Kelich J, Rice C, Skordalakes E Comput Struct Biotechnol J. 2022 Jan 11;20:675-684. doi:, 10.1016/j.csbj.2022.01.005. eCollection 2022. PMID:35140887[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Liu D, Safari A, O'Connor MS, Chan DW, Laegeler A, Qin J, Songyang Z. PTOP interacts with POT1 and regulates its localization to telomeres. Nat Cell Biol. 2004 Jul;6(7):673-80. Epub 2004 Jun 6. PMID:15181449 doi:http://dx.doi.org/10.1038/ncb1142
- ↑ de Lange T. Shelterin: the protein complex that shapes and safeguards human telomeres. Genes Dev. 2005 Sep 15;19(18):2100-10. PMID:16166375 doi:10.1101/gad.1346005
- ↑ O'Connor MS, Safari A, Xin H, Liu D, Songyang Z. A critical role for TPP1 and TIN2 interaction in high-order telomeric complex assembly. Proc Natl Acad Sci U S A. 2006 Aug 8;103(32):11874-9. Epub 2006 Jul 31. PMID:16880378 doi:0605303103
- ↑ Zaug AJ, Podell ER, Nandakumar J, Cech TR. Functional interaction between telomere protein TPP1 and telomerase. Genes Dev. 2010 Mar 15;24(6):613-22. doi: 10.1101/gad.1881810. PMID:20231318 doi:10.1101/gad.1881810
- ↑ Wang F, Podell ER, Zaug AJ, Yang Y, Baciu P, Cech TR, Lei M. The POT1-TPP1 telomere complex is a telomerase processivity factor. Nature. 2007 Feb 1;445(7127):506-10. Epub 2007 Jan 21. PMID:17237768 doi:nature05454
- ↑ Aramburu T, Kelich J, Rice C, Skordalakes E. POT1-TPP1 binding stabilizes POT1, promoting efficient telomere maintenance. Comput Struct Biotechnol J. 2022 Jan 11;20:675-684. doi:, 10.1016/j.csbj.2022.01.005. eCollection 2022. PMID:35140887 doi:http://dx.doi.org/10.1016/j.csbj.2022.01.005
