Figure 3.

Sequence alignment of the flip and flop domains of GluR1-GluR4 subunits. The three regions of heterogeneity between the flip and flop splice variants (regions 1, 2, and 3) are labeled. Asterisks indicate two other positions that were exchanged in the GluR2i subunit with the residue in the equivalent position in the GluR2o subunit. In subsequent figures, an open rectangle will refer to the flip domain, and a dark rectangle will refer to the flop domain. Exchanges will then be highlighted in the appropriate color.