APLF (C2orf13) is a Novel Human Protein Involved in the Cellular Response to Chromosomal DNA Strand Breaks

Iles, Natasha, Rulten, Stuart L., El-Khamisy, Sherif F. and Caldecott, Keith W. (2007) APLF (C2orf13) is a Novel Human Protein Involved in the Cellular Response to Chromosomal DNA Strand Breaks. Molecular and Cellular Biology, 27 (10). pp. 3793-3803. ISSN 0270-7306

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Aprataxin and polynucleotide kinase (PNK) are DNA end processing factors that are recruited into the DNA single- and double-strand break repair machinery through phosphorylation-specific interactions with XRCC1 and XRCC4, respectively. These interactions are mediated through a divergent class of forkhead-associated (FHA) domain that binds to peptide sequences in XRCC1 and XRCC4 that are phosphorylated by casein kinase 2 (CK2). Here, we identify the product of the uncharacterized open reading frame C2orf13 as a novel member of this FHA domain family of proteins and we denote this protein APLF (aprataxin- and PNK-like factor). We show that APLF interacts with XRCC1 in vivo and in vitro in a manner that is stimulated by CK2. Yeast two-hybrid analyses suggest that APLF also interacts with the double-strand break repair proteins XRCC4 and XRCC5 (Ku86). We also show that endogenous and yellow fluorescent protein-tagged APLF accumulates at sites of H2O2 or UVA laser-induced chromosomal DNA damage and that this is achieved through at least two mechanisms: one that requires the FHA domain-mediated interaction with XRCC1 and a second that is independent of XRCC1 but requires a novel type of zinc finger motif located at the C terminus of APLF. Finally, we demonstrate that APLF is phosphorylated in a DNA damage- and ATM-dependent manner and that the depletion of APLF from noncycling human SH-SY5Y neuroblastoma cells reduces rates of chromosomal DNA strand break repair following ionizing radiation. These data identify APLF as a novel component of the cellular response to DNA strand breaks in human cells.

Item Type: Article
Schools and Departments: School of Life Sciences
Subjects: Q Science > QP Physiology
Depositing User: Stuart Rulten
Date Deposited: 16 Jul 2007
Last Modified: 02 Jul 2019 21:21
URI: http://sro.sussex.ac.uk/id/eprint/1114
Google Scholar:40 Citations

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