Fig. 2: NHA2ΔN oligomerization.
From: Structure, mechanism and lipid-mediated remodeling of the mammalian Na+/H+ exchanger NHA2
a, Cartoon representation of the NHA2ΔN homodimer viewed from the cytoplasmic side and colored as in Fig. 1c, with the dotted circle highlighting one of the two oligomerization contacts formed between TM −1 (blue) and TM8 (green) on the neighboring protomer. Top inset: zoomed-in view showing the potential polar contacts between the strictly conserved residues D330–Q331 in the TM8–TM9 loop of one protomer (yellow sticks, labeled) and Arg85 in TM −1 of the other protomer (yellow sticks, labeled). Bottom inset: zoomed-in view showing the oligomerization interactions formed by hydrophobic residues (yellow spheres, labeled) between TM −1 (blue) and TM8 (green). b, Representative FSEC traces of DDM-CHS solubilized NHA2ΔN (blue) and NHA2ΔN non-functional mutant D277C–D278C (orange) from membranes isolated following heterologous expression in the salt-sensitive yeast strain S. cerevisiae AB11c9,32. FSEC traces were compared to the NHA2ΔN loop mutant D330A–Q331A (green) and the TM −1 deletion mutant NHA2ΔTM−1 (red). Melting temperatures (TM) for purified NHA2ΔN-GFP and NHA2ΔTM−1-GFP in DDM/CHS were calculated from the melting curves in Supplementary Figs. 1c and 3c. c, Normalized lithium sensitivity of NHA2ΔN and derived constructs grown in the AB11c strain in the presence of 20 mM LiCl (see Extended Data Fig. 1b and Supplementary Fig. 3b,c for cell growth in the presence of different lithium concentrations and non-induced controls). Errors bars represent the mean ± s.e.m. of n = 4 biologically independent samples. d, Electrostatic surface representation of the outward-facing NHA2ΔN homodimer from the cytoplasm (left) and the extracellular side (right). The dashed circles and asterisks highlight the regions of positively charged surfaces between the two protomers.
