Table 1.
Reactivity of human and mouse P-gp and chimeras with human P-gp-specific MRK-16, UIC2 and 4E3 antibodies.
| P-gp/Chimera | Description | Antibody binding | ||
|---|---|---|---|---|
| MRK-16 | 4E3 | UIC2 | ||
| Human P-gp | Human P-gp | ++++ | ++++ | ++++ |
| Mouse P-gp | Mouse P-gp | −− | −− | −− |
| MMHH | Mouse 1-644 (h 1-648) – human 649-1280 | −− | −− | −− |
| HHMM | Human 1-648 – mouse 644-1270 (h 648-1280) | −− | −− | −− |
| HHMM-ECL4&6-h17* | TMH7/ECL4: S725(h729)A, V726(h730)I, V731(h735)I, V732(h736)I, N737(h741)R, G738(h742)I, G739(h743)D, P740(h744)D, Q7429(h748)R, I757(h761)A TMH11/ECL6/TMH12: A951(h955)G, T961(h965)A, Q962(h966)H, Q963(h967)K, T966(h970)S, N969(h973)D, I977(h981)V | ++++ | ++++ | ++++ |
| HHMM-ECL4&6-h9 | ECL4: N737(h741)R, G738(h742)I, G739(h743)D, P740(h744)D, Q744(h748)K; ECL6: T961(h965)A, Q962(h966)H, Q963(h967)K, T966(h970)S | ++++ | +++ | ++++ |
| HHMM-ECL4-h5 | ECL4: N737(h741)R, G738(h742)I, G739(h743)D, P740(h744)D, Q744(h748)K | ++++ | ++++ | ++++ |
| HHMM-ECL6-h4 | ECL6: T961(h965)A, Q962(h966)H, Q963(h967)K, T966(h970)S | −− | −− | −− |
| MMHH-ECL1-h5# | ECL1: S85(h86)E, 88(h89)M, 89(h89)S, 90(h90)N, M94(h95)R | +++ | +++ | −− |
| Mouse P-gp-ECL1&4-h18# | ECL1: S77(h78)I, S80(81)N, V81(h82)A, V84(h85)L, S85(h86)E, K86(h87)D, N87(h88)L, 88(h89)M, 89(h90)S, 90(h91)N, S91(h92)I, M94(h95)R, E96(h97)D; ECL4: N740(h741)R, G741(h742)I, G742(h743)D, P743(h744)D, Q748(h748)K | ++++ | ++++ | ++++ |
| Mouse P-gp-ECL13&4-h19# | ECL1: S77(h78)I, S80(81)N, V81(h82)A, V84(h85)L, S85(h86)E, K86(h87)D, N87(h88)L, 88(h89)M, 89(h90)S, 90(h91)N, S91(h92)I, M94(h95)R, E96(h97)D; ECL3: K323(h324)G; ECL4: N740(h741)R, G741(h742)I, G742(h743)D, P743(h744)D, Q748(h748)K | +++++ | ++++ | +++++ |
*Contains mutations that go inside transmembrane helices 7, 11, and 12.
#Numbering in the final sequence is shifted by −1 compared to the human due to deletion in the mouse P-gp at position 12.
The antibody binding to each P-gp chimera was compared to human P-gp and categorized into six levels: –, no binding; +, 25%; ++, 50%, +++, 75%; ++++, 100% and +++++, >100% binding compared to human P-gp. The results are compiled from three to five independent experiments and data from a representative experiment are given in Figs 2–6. For human-mouse P-gp chimeras, the human amino acids and their numbers are given in parentheses.