APOBEC3F is a cytidine deaminase that functions as an innate immune restriction factor against HIV-1 and other retroviruses 1. The protein localizes to mRNA processing bodies (P-bodies) where it forms ribonucleoprotein complexes with other regulatory proteins 2. APOBEC3F restricts HIV-1 replication through both deamination-dependent and -independent mechanisms by converting cytosine to uracil in single-stranded viral DNA, leading to detrimental G-to-A hypermutations in the proviral genome 3. The enzyme is packaged into HIV-1 virions and can form heterodimers with APOBEC3G, which may provide partial protection from viral degradation 34. HIV-1 counteracts APOBEC3F through its Vif protein, which hijacks the Cul5-containing E3 ubiquitin ligase complex to induce APOBEC3F polyubiquitination and proteasomal degradation 5. However, APOBEC3F shows some resistance to Vif-mediated degradation compared to other APOBEC3 proteins 6. Genetic variations in APOBEC3F, particularly the I231V variant, are associated with lower HIV-1 viral loads and slower disease progression in clinical cohorts 6. The deamination activity of APOBEC3F is influenced by the length of single-stranded DNA substrates and the relative concentrations of enzyme and substrate 7.