ARHGAP25 is a Rho GTPase-activating protein that functions as a negative regulator of Rho family small GTPases, particularly Rac, by converting them from an active GTP-bound to an inactive GDP-bound state 12. The protein localizes to lamellipodia where it suppresses Rac-dependent lamellipodia formation and cell spreading, with its activity regulated by septin2 3. ARHGAP25 controls actin cytoskeletal organization and cell migration through direct regulation of Rac1/PAK1 signaling 4. In neutrophils, ARHGAP25 exhibits GTP-GDP cycle-dependent interactions with small GTPases including RAC2 and RHOG, suggesting dynamic regulation of its GAP activity 2. The protein plays significant roles in immune cell function, particularly in phagocyte effector functions and leukocyte infiltration during inflammatory responses 5. ARHGAP25 is implicated in various diseases, including serving as a tumor suppressor in breast cancer through inhibition of Wnt/β-catenin signaling 4, contributing to vasculogenic mimicry regulation in non-small cell lung cancer 6, and modulating contact hypersensitivity responses 5. Additionally, variants in ARHGAP25 have been identified as novel genetic loci associated with Alzheimer's disease risk 7 and as recurrent mutations in T-large granular lymphocyte leukemia 8.