Shelterin: the protein complex that shapes and safeguards human telomeres.
Added by telomerase, arrays of TTAGGG repeats specify the ends of human chromosomes. A complex formed by six telomere-specific proteins associates with this sequence and protects chromosome ends. By analogy to other chromosomal protein complexes such as condensin and cohesin, I will refer to this complex as shelterin. Three shelterin subunits, TRF1, TRF2, and POT1 directly recognize TTAGGG repeats. They are interconnected by three additional shelterin proteins, TIN2, TPP1, and Rap1, forming a complex that allows cells to distinguish telomeres from sites of DNA damage. Without the protective activity of shelterin, telomeres are no longer hidden from the DNA damage surveillance and chromosome ends are inappropriately processed by DNA repair pathways. How does shelterin avert these events? The current data argue that shelterin is not a static structural component of the telomere. Instead, shelterin is emerging as a protein complex with DNA remodeling activity that acts together with several associated DNA repair factors to change the structure of the telomeric DNA, thereby protecting chromosome ends. Six shelterin subunits: TRF1, TRF2, TIN2, Rap1, TPP1, and POT1.
de Lange
Titia
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The Rockefeller University, New York, New York 10021, USA. delange@mail.rockfeller.edu
D000954:Antigens, Surface; D001665:Binding Sites; D015815:Cell Adhesion Molecules; D043171:Chromosomal Instability; D004249:DNA Damage; D006801:Humans; D008562:Membrane Glycoproteins; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism*; D010447:Peptide Hydrolases; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry; D011506:Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D000089804:Shelterin Complex; D020080:Tandem Repeat Sequences; D016615:Telomere / Q000235:genetics / Q000378:metabolism*; D034501:Telomere-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D035321:Telomeric Repeat Binding Protein 1; D035341:Telomeric Repeat Binding Protein 2; D020827:rap1 GTP-Binding Proteins
C495876:ACD protein, human; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D008562:Membrane Glycoproteins; D046912:Multiprotein Complexes; C440849:POT1 protein, human; D021122:Protein Subunits; D011506:Proteins; D000089804:Shelterin Complex; C085434:TINAG protein, human; D034501:Telomere-Binding Proteins; D035321:Telomeric Repeat Binding Protein 1; D035341:Telomeric Repeat Binding Protein 2; D010447:Peptide Hydrolases; D020827:rap1 GTP-Binding Proteins