FMN2 (formin 2) is an actin-binding protein that plays crucial roles in cytoskeletal organization and cellular processes. As an actin nucleation factor, FMN2 promotes actin filament assembly in collaboration with SPIRE1 and SPIRE2, contributing to actin cytoskeleton reorganization 12. The protein is essential for asymmetric spindle positioning and polar body extrusion during female meiosis, with mouse studies showing that Fmn2 mutants exhibit meiosis I arrest 3. Beyond cytoskeletal functions, FMN2 responds to cellular stress by protecting CDKN1A from degradation, thereby promoting stress-induced cell cycle arrest and protecting against apoptosis 4. In the nucleus, FMN2 collaborates with SPIRE proteins to assemble nuclear actin filaments following DNA damage, facilitating chr1 movement and DNA repair 5. Clinical relevance includes associations with intellectual developmental disorder, autosomal recessive 47, and corpus callosum malformations in 1q43q44 deletion syndrome 6. FMN2 also functions as a microtubule dynamics regulator in axon regeneration 7 and shows overexpression in acute lymphoblastic leukemia, suggesting oncogenic potential 8. Additionally, FMN2 promotes chemoresistance in ovarian cancer through immunosuppressive mechanisms 9.