FANCM and FAAP24 function in ATR-mediated checkpoint signaling independently of the Fanconi anemia core complex.
The Fanconi anemia (FA) pathway is implicated in DNA repair and cancer predisposition. Central to this pathway is the FA core complex, which is targeted to chromatin by FANCM and FAAP24 following replication stress. Here we show that FANCM and FAAP24 interact with the checkpoint protein HCLK2 independently of the FA core complex. In addition to defects in FA pathway activation, downregulation of FANCM or FAAP24 also compromises ATR/Chk1-mediated checkpoint signaling, leading to defective Chk1, p53, and FANCE phosphorylation; 53BP1 focus formation; and Cdc25A degradation. As a result, FANCM and FAAP24 deficiency results in increased endogenous DNA damage and a failure to efficiently invoke cell-cycle checkpoint responses. Moreover, we find that the DNA translocase activity of FANCM, which is dispensable for FA pathway activation, is required for its role in ATR/Chk1 signaling. Our data suggest that DNA damage recognition and remodeling activities of FANCM and FAAP24 cooperate with ATR/Chk1 to promote efficient activation of DNA damage checkpoints.
Collis
Spencer J
SJ
DNA Damage Response Laboratory, Cancer Research UK, Clare Hall, EN6 3LD South Mimms, UK.
Ciccia
Alberto
A
Deans
Andrew J
AJ
Horejsí
Zuzana
Z
Martin
Julie S
JS
Maslen
Sarah L
SL
Skehel
J Mark
JM
Elledge
Stephen J
SJ
West
Stephen C
SC
Boulton
Simon J
SJ
D002460:Cell Line; D004249:DNA Damage; D004265:DNA Helicases / Q000172:deficiency / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D004277:DNA, Single-Stranded / Q000235:genetics; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D005199:Fanconi Anemia / Q000235:genetics* / Q000378:metabolism; D051856:Fanconi Anemia Complementation Group Proteins; D016678:Genome; D006367:HeLa Cells; D006801:Humans; D007668:Kidney; D008938:Mitosis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016196:S Phase; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C518296:FAAP24 protein, human; D051856:Fanconi Anemia Complementation Group Proteins; C066780:Clk dual-specificity kinases; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; C518295:FANCM protein, human; D004265:DNA Helicases