Figure 2.

Phylogenetic tree of the rhomboid family. The sequences and their regions used for the construction of the tree are exactly those shown in Fig. 1. The color coding and abbreviations are as in Fig. 1. The two major eukaryotic subfamilies are denoted as RHO and PARL (see text) and four clusters containing unexpected, from a phylogenetic viewpoint, sets of species are denoted 1-4. Although the tree is shown in a rooted form for convenience, this is an unrooted tree; in particular, the placement of the "root" in the midst of the PARL subfamily is arbitrary. Internal nodes with at least 70% RELL bootstrap supported are denoted by circles. Domain architectures are connected to the respective proteins by brackets or by lines. The domain key is shown in the bottom of the figure.