TPP1 (IPR019437) is a constituent of the shelterin complex TPP1/Est3. Est3 (TPP1) is a component of the telomerase holoenzyme (shelterin complex) that is involved in yeast telomere replication. Studies have demonstrated that TPP1 dimerizes and attaches to both DNA and RNA. Furthermore, TPP1 induces the dissociation of RNA/DNA heteroduplexes. A novel GTPase is the yeast telomerase protein TPP1 (Est3). The N-terminus of TPP1 may serve as the binding surface for TIN2, while the C-terminus may bind to POT1, thereby tethering POT1 to the shelterin complex. The complex enhances the activity and synthesis capacity of the human telomerase core enzyme when it binds to telomeric DNA, thereby aiding in the preservation of telomere length. Six proteins make up the human shelterin complex: telomeric repeat binding factor 1 (TRF1), TRF2, repressor/activator protein 1 (RAP1), TRF1-interacting nuclear protein 2 (TIN2), TIN2-interacting protein 1 (TPP1), also known as ACD of adrenocortical dysplasia protein, and protection of telomeres 1 (POT1).