| FANCA serves as a core scaffold within the Fanconi anemia (FA) nuclear complex alongside FANCB, FANCC, FANCE, FANCF, FANCG, FANCL, and FANCM, orchestrating interstrand crosslink repair and genome stability maintenance through coordinated protein interactions. FANCA organizes tetratricopeptide repeats and leucine zippers that facilitate assembly of the multi-subunit complex at chromatin lesions while binding Hsp90 chaperone for stability and nuclear trafficking. Upon DNA damage from crosslinkers like mitomycin C, the FA complex activates FANCL E3 ligase to mono-ubiquitinate FANCD2-FANCI heterodimer, recruiting downstream effectors FANCJ/BRIP1, FANCD1/BRCA2, and FANCN/PALB2 for fork remodeling, translesion synthesis, and homologous recombination via strand invasion coordinated with the BRCA1/53BP1 axis. FANCA directly catalyzes single-strand annealing of resected double-strand breaks independent of canonical FA pathway components, annealing complementary overhangs through bidirectional strand exchange that competes with RAD52 to favor error-free repair outcomes during replication stress. Hsp90 association stabilizes FANCA conformation against proteasomal degradation, with 17-AAG inhibition disrupting nuclear localization and impairing FANCD2 activation that sensitizes cells to crosslinking agents. FANCA shuttles to pericentriolar material and kinetochores to regulate the spindle assembly checkpoint via BUB1-BUBR1 phosphorylation networks, preventing anaphase onset until bipolar attachment while suppressing chromosome fragmentation through ultrafine bridge resolution. FANCA safeguards hematopoietic stem cell quiescence and self-renewal by integrating replication stress responses with mitotic fidelity in bone marrow niches. |
Lane 1: 293T, Lane 2: HCT116, Lane 3: Hela, Lane 4: HT-29
