Phospho-FANCA S1449 is increased on chromatin after DNA damage and FANCA S1449A binds FANCG. (A) Chromatin extracts were prepared from HeLa cells treated with 1 μM MMC for 18 hours. Extracts were separated by SDS-PAGE and immunoblotted for phospho-FANCA S1449, total FANCA, and topoisomerase II as a loading control. (B) Whole cell extracts from HeLa cells expressing Flag-FANCA, Flag-FANCA S1449A, or the vector control and treated with 1 μM MMC for 6 hours were immunoprecipitated with anti-Flag. Immunoprecipitated proteins were separated by SDS-PAGE and immunoblotted for FANCA and FANCG. topoII indicates topoisomerase II; P-S1449, phosphoserine 1449; and IP, immunoprecipitation.