The virapower kit is used to express genes in specific cell lines, in this case the expression of the Na-channel protein in rat myocetes. This is not relevant for figure 2, however.
In Fig. 2a the aminoacid change in the ankyrin binding region of Nav1.5 of humans with the Brugada-syndrom is shown (that is that exchange migh be associated with it).
The next thing they tested is whether the mutation does have an effect on ankyrin-binding.
For this they fused the region in which the motif is located (loop2) to the neurofascin EC domain. This is done on the DNA-level of course, and since the resulting cotains parts of two different proteins (neuofascin and Nav1.5 loop) it is called a chimeric protein. The whole thing is only a testsytem to determine, whether the mutation does result in a loss of ankyring binding (with controls), and they show that it does (Fig 2b), same with another approach (yeast-two hybrid assays, 2c).
Then the looked, which ankyrin isoforms exist in heart tissue and identified it with antibodies (Fig. 2D), and the identified isoform is the 190 kDa ankyrin-G (kDa is the molecular weight and is determined according to their mobility in gels.
And finally they looked if Nav1.5 really interacts to this specific ankyrin-form. The first band in 2E shows Nav1.5protein, which means that protein was bound to ankyrin and could be acquired that way. lane 2 is the negative and lane 3 the positive control.
