Structure analysis of FAAP24 reveals single-stranded DNA-binding activity and domain functions in DNA damage responseWang, Y., Han, X., Wu, F., Leung, J.W., Lowery, M.G., Do, H., Chen, J., Shi, C., Tian, C., Li, L., Gong, W.
(2013) Cell Res. --: --
- PubMed: 23999858
- DOI: 10.1038/cr.2013.124
- Primary Citation of Related Structures:  2M9M
- PubMed Abstract:
The FANCM/FAAP24 heterodimer has distinct functions in protecting cells from complex DNA lesions such as interstrand crosslinks. These functions rely on the biochemical activity of FANCM/FAAP24 to recognize and bind to damaged DNA or stalled replicat ...
The FANCM/FAAP24 heterodimer has distinct functions in protecting cells from complex DNA lesions such as interstrand crosslinks. These functions rely on the biochemical activity of FANCM/FAAP24 to recognize and bind to damaged DNA or stalled replication forks. However, the DNA-binding activity of this complex was not clearly defined. We investigated how FAAP24 contributes to the DNA-interacting functions of the FANCM/FAAP24 complex by acquiring the N-terminal and C-terminal solution structures of human FAAP24. Modeling of the FAAP24 structure indicates that FAAP24 may possess a high affinity toward single-stranded DNA (ssDNA). Testing of various FAAP24 mutations in vitro and in vivo validated this prediction derived from structural analyses. We found that the DNA-binding and FANCM-interacting functions of FAAP24, although both require the C-terminal (HhH)2 domain, can be distinguished by segregation-of-function mutations. These results demonstrate dual roles of FAAP24 in DNA damage response against crosslinking lesions, one through the formation of FANCM/FAAP24 heterodimer and the other via its ssDNA-binding activity required in optimized checkpoint activation.
Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.