APLF (C2orf13) facilitates nonhomologous end-joining and undergoes ATM-dependent hyperphosphorylation following ionizing radiation

作者：Macrae Chloe J; McCulloch Richard D; Ylanko Jarkko; Durocher Daniel; Koch C Anne^*

来源：DNA Repair, 2008, 7(2): 292-302.

DOI：10.1016/j.driarep.2007.10.008

• NHEJ
• APLF
• FHA domains
• ATM
• phosphorylation
• CK2

Nonhomologous end-joining (NHEJ) is the major mammalian DNA double-strand break (DSB) repair pathway of DSBs induced by DNA damaging agents. NHEJ is initiated by the recognition of DSBs by the DNA end-binding heterodimer, Ku, and the final step of DNA end-joining is accomplished by the XRCC4-DNA ligase IV complex. We demonstrate that Aprataxin and PNK-like factor (APLF), an endo/exonuclease with an FHA domain and unique zinc fingers (ZFs), interacts with both Ku and XRCC4-DNA ligase IV in human cells. The interaction of APLF with XRCC4-DNA ligase IV is FHA- and phospho-dependent, and is mediated by CK2 phosphorylation of XRCC4 in vitro. In contrast, APLF associates with Ku independently of the FHA and ZF domains, and APLF complexes with Ku at DNA ends. APLF undergoes ionizing radiation (IR) induced ATM-dependent hyperphosphorylation at serine residue 116, which is highly conserved across mammalian APLF homologues. We demonstrate further that depletion of APLF in human cells by siRNA is associated with impaired NHEJ. Collectively, t

• 出版日期2008-2-1