The shelterin complex. Telomere DNA extremity is schematized at the junction between double strand DNA an 3′ single-strand overhang. The shelterin complex is composed of 2 double-strand telomeric sequence–binding proteins (TRF1 and TRF2), of one 3′overhang-binding protein (POT1) and of 3 others proteins (TIN2, TPP1, RAP1), essential for the complex constitution and stabilization. This complex inhibits DDR activation and ATM and/or ATR activation.