Tankyrase 1 (TNKS1)

Tankyrase 1, a human telomeric poly(ADP-ribose) polymerase, was originally identified through its interaction with TRF1, a negative regulator of telomere length. Tankyrase 1 ADP-ribosylates TRF1 in vitro, and its overexpression induces telomere elongation in human cancer cells. Surprisingly, dissection of this domain reveals multiple discrete and overlapping binding sites for TRF1 and TAB182. Five well conserved ankyrin repeat clusters in tankyrase 1. Although each of the five ankyrin repeat clusters independently binds to TRF1, only three of the five bind toTAB182. These findings suggest that tankyrase 1 may act as a scaffold for large molecular mass complexes made up of multiple binding proteins. Potential roles for tankyrase 1-mediated higher order complexes at telomeres and at other subcellular sites.