Basigin drives intracellular accumulation of l-lactate by harvesting protons and substrate anions
Fig 5
Two oppositely charged surface patches in the BSG Ig-I domain.
(A) Poisson-Boltzmann electrostatic potential of the extracellular domain of BSG var2 (PDB #3B5H) reveals two oppositely charged surface patches in the BSG Ig-I domain; the red/blue scale covers the range of –3 kT e– to +3 kT e–. (B–D) Effect of replacing charged residues in the BSG Ig-I domain by neutral ones on the electrostatic potential (left) and the l-lactate transport of fused MCT1 (right). The five Glu residues of the negative patch (pos. 114, 118, 120, 168, 172) were changed to Gln (B, ●), the five Lys/Arg residues of the positive patch (pos. 108, 111, 127, 201, 203) were mutated to Ala altogether (C, ●) or in two pairs of two (D, Lys108,111Ala: ●, Arg201,203Ala: 〇). The electrostatic surface in D shows wild-type BSG for better orientation. The gray shading indicates the corridor between the uptake capacities of MCT1 fused with wild-type BSG Ig-I (upper border, from Fig 2C) and MCT1 alone (lower border, from Fig 1D).