| Primary Identifier | IPR019437 | Type | Domain |
| Short Name | TPP1/Est3 |
| description | TPP1 (Est3 in yeast) is a component of the telomerase holoenzyme (shelterin complex), involved in telomere replication. It has been demonstrated that TPP1 dimerises and binds to DNA and RNA. Furthermore, TPP1 stimulates the dissociation of RNA/DNA hetero-duplexes [, ]. Yeast telomerase protein TPP1 (Est3) is a novel type of GTPase []. The key residues in Saccharomyces cerevisiae are an Asp at residue 86 and the Arg at residue 110. The Asp is totally conserved in the family, whereas the Arg is not so well conserved. The N-terminal of TPP1 is likely to be the binding surface for TIN2, whereas the C terminus probably binds to POT1, thereby tethering POT1 to the shelterin complex []. The complex bound to telomeric DNA increases the activity and processivity of the human telomerase core enzyme, thus helping to maintain the length of the telomeres [, , ].The human shelterin complex includes six proteins: telomere 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 from adrenocortical dysplasia protein; and protection of telomeres 1 (POT1) []. |
