M. tuberculosis secretes the EsxA effector through its ESX-1 system, which orchestrates CBL-b-mediated polyubiquitination and subsequent proteasomal degradation of Ubc9 (K48-linked at Lys74), ultimately reducing Ubc9 levels by 80% within 6 h of infection (Anang et al., 2023). Here, UBE2I is linked to infection.