POT1 is responsible for binding to and protecting the 3' single-stranded DNA (ssDNA) overhang at most eukaryotic telomeres [1,2]. This is an insertion domain found at the C-terminal, described as Holliday junction resolvase-like domain (HJRL) in [1].

1: Structural insights into POT1-TPP1 interaction and POT1 C-terminal mutations in human cancer. Chen C, Gu P, Wu J, Chen X, Niu S, Sun H, Wu L, Li N, Peng J, Shi S, Fan C, Huang M, Wong CC, Gong Q, Kumar-Sinha C, Zhang R, Pusztai L, Rai R, Chang S, Lei M; Nat Commun. 2017;8:14929. PMID:28393832

2: Structural and functional analysis of the human POT1-TPP1 telomeric complex. Rice C, Shastrula PK, Kossenkov AV, Hills R, Baird DM, Showe LC, Doukov T, Janicki S, Skordalakes E; Nat Commun. 2017;8:14928. PMID:28393830