Mass spectrometry runs and analysis of host proteins co-immunoprecipitated with RABV M protein

To explore the role of the matrix protein in RABV infection of host cells, we looked for host proteins that interact with the RABV M protein. We performed Flag-tag-based immunoprecipitation of lysates of HEK293T cells transfected with plasmids expressing either N- or C-terminally Flag-tagged M protein (M-NF or M-CF, respectively), and identified host proteins that interacted with the M proteins by using mass spectrometry (MS). Proteins were detected in lysates of cells transfected with the plasmid expressing Flag-tagged M proteins but not in those of cells transfected with the control plasmid. We identified a total of 2,672 host proteins that co-immunoprecipitated with the M protein; 492 proteins co-immunoprecipitated to both M-NF and M-CF, 1,761 proteins co-immunoprecipitated with M-NF only, and 419 proteins co-immunoprecipitated with M-CF only.