However, a higher proportion of polytopic membrane domains could be classified if smaller families were considered (Figure 4a).

These families contain well-amplified membrane domains, with total numbers of 289, 250, and 216, respectively.

Numbers of membrane domains in classified families were counted and analyzed in all genomes studied.

This editing site is located in the " pore loop" of the second membrane domain (M2).

With the exception of the presence of an integral membrane domain, these are identical to their secreted forms.

The integral membrane domain is composed of 3 main proteins: subunits 6, A6L, and 9.

Polytopic membrane domains were identified using the loop size between TM-helices as a guide.

So the unusually large number of polytopic membrane domains is likely to be caused by protein amplification in a few families.

We went through a relatively conservative procedure to identify potential families of polytopic membrane domains.

The membrane domain senses signals for its degradation.