Fig 1: Cis- and trans-interactions of APOL1, APOL3, PI4KB, and ARF1(A) Representative SPR sensorgrams of immobilized PI4KB H1-H3 interactions with recombinant APOL1, APOL1Δ, APOL3, NCS1, or NCS1 L89K (n = 3). As in (B)–(I), interaction was performed in 50 μM CaCl2.(B) SPR sensorgrams of immobilized APOL1 CTD interaction with the APOL1 NTD peptide, measured at different pHs (n = 3).(C) BLI measurements of immobilized PI4KB sequential interactions with recombinant APOL1Δ or APOL3 as indicated (n = 3).(D) Representative SPR sensorgrams of immobilized ARF1p interaction with PI4KB H1-H3 or APOL1/3 HC1 peptides (n = 3).(E) Representative SPR sensorgrams of immobilized ARF1p interaction with recombinant APOL3, APOL1, APOL3Δ, or APOL1Δ (n = 3). Notice the different binding scales between the two graphs.(F) BLI measurement of immobilized recombinant ARF1 interaction with recombinant APOL3 (n = 3).(G) Representative SPR sensorgrams of immobilized ARF1p sequential interactions with recombinant APOL3 or PI4KB as indicated (n = 3).(H) BLI measurements of immobilized PI4KB sequential interactions with recombinant APOL3 or ARF1 as indicated (n = 3).(I) Immunofluorescence analysis of APOL3-V5 co-localization with PI4KB in WT podocytes treated or not with poly(I:C). Bar: 20 μm; blue: nucleus (DAPI). n = 3; Mann-Whitney test, ∗p < 0.05. Error bars represent the standard deviation.