Patient-derived C-terminal mutation of FANCI causes protein mislocalization and reveals putative EDGE motif function in DNA repair.
Fanconi anemia (FA) is a rare familial genome instability syndrome caused by mutations in FA genes that results in defective DNA crosslink repair. Activation of the FA pathway requires the FA core ubiquitin ligase complex-dependent monoubiquitination of 2 interacting FA proteins, FANCI and FANCD2. Although loss of either FANCI or FANCD2 is known to prevent monoubiquitination of its respective partner, it is unclear whether FANCI has any additional domains that may be important in promoting DNA repair, independent of its monoubiquitination. Here, we focus on an FA-I patient-derived FANCI mutant protein, R1299X (deletion of 30 residues from its C-terminus), to characterize important structural region(s) in FANCI that is required to activate the FA pathway. We show that, within this short 30 amino acid stretch contains 2 separable functional signatures, a nuclear localization signal and a putative EDGE motif, that is critical for the ability of FANCI to properly monoubiquitinate FANCD2 and promote DNA crosslink resistance. Our study enable us to conclude that, although proper nuclear localization of FANCI is crucial for robust FANCD2 monoubiquitination, the putative FANCI EDGE motif is important for DNA crosslink repair.
Department of Biochemistry, New York University School of Medicine, New York, NY, USA.
Luca
L
Colnaghi
Mathew J K
MJ
Jones
Xiomaris M
XM
Cotto-Rios
Detlev
D
Schindler
Helmut
H
Hanenberg
Tony T
TT
Huang
D021581:Active Transport, Cell Nucleus; D020816:Amino Acid Motifs; D001483:Base Sequence; D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics*; D005199:Fanconi Anemia / Q000235:genetics* / Q000378:metabolism*; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000235:genetics / Q000378:metabolism; D051856:Fanconi Anemia Complementation Group Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D019913:Nuclear Localization Signals; D034741:RNA, Small Interfering / Q000235:genetics; D017384:Sequence Deletion; D054875:Ubiquitination
C499905:FANCD2 protein, human; C519921:FANCI protein, human; D052236:Fanconi Anemia Complementation Group D2 Protein; D051856:Fanconi Anemia Complementation Group Proteins; D019913:Nuclear Localization Signals; D034741:RNA, Small Interfering