A novel human AP endonuclease with conserved zinc-finger-like motifs involved in DNA strand break responses

• Published in: The EMBO journal 2007-04, Vol.26 (8), p.2094-2103
• Main Authors: Kanno, Shin-ichiro, Kuzuoka, Hiroyuki, Sasao, Shigeru, Hong, Zehui, Lan, Li, Nakajima, Satoshi, Yasui, Akira
• Format: Article
• Language: English
• Subjects: Adenosine diphosphate; Amino Acid Sequence; Animals; Antigens, Nuclear; AP endonuclease; Apoptosis; Cell Line, Tumor; Cellular biology; Chromatography, Liquid; CYR motif; Deoxyribonucleic acid; DNA; DNA Damage; DNA Ligase ATP; DNA Ligases - metabolism; DNA repair; DNA Repair - physiology; DNA-(Apurinic or Apyrimidinic Site) Lyase - genetics; DNA-(Apurinic or Apyrimidinic Site) Lyase - metabolism; DNA-Binding Proteins - metabolism; double-strand breaks; Drosophila; EMBO13; Fluorescent Antibody Technique; Genomics; Humans; Ku Autoantigen; Mass Spectrometry; Methane; Mice; Mice, Knockout; Molecular Sequence Data; Oligonucleotides; PARP1; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases - metabolism; Poly-ADP-Ribose Binding Proteins; Protein Structure, Tertiary; Proteins; RNA, Small Interfering - genetics; Sequence Alignment; single-strand breaks; Sulfonates; Zinc; Zinc Fingers - genetics
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1038/sj.emboj.7601663

DNA damage causes genome instability and cell death, but many of the cellular responses to DNA damage still remain elusive. We here report a human protein, PALF ( P NK and A PTX‐ l ike F HA protein), with an FHA (forkhead‐associated) domain and novel zinc‐finger‐like CYR (cysteine–tyrosine–arginine) motifs that are involved in responses to DNA damage. We found that the CYR motif is widely distributed among DNA repair proteins of higher eukaryotes, and that PALF, as well as a Drosophila protein with tandem CYR motifs, has endo‐ and exonuclease activities against abasic site and other types of base damage. PALF accumulates rapidly at single‐strand breaks in a poly(ADP‐ribose) polymerase 1 (PARP1)‐dependent manner in human cells. Indeed, PALF interacts directly with PARP1 and is required for its activation and for cellular resistance to methyl‐methane sulfonate. PALF also interacts directly with KU86, LIGASEIV and phosphorylated XRCC4 proteins and possesses endo/exonuclease activity at protruding DNA ends. Various treatments that produce double‐strand breaks induce formation of PALF foci, which fully coincide with γH2AX foci. Thus, PALF and the CYR motif may play important roles in DNA repair of higher eukaryotes.