Fig. 4.

Phylogenetic analysis of human, mouse and yeast ABC proteins. Phylogenetic analyses of sterolin and ABC proteins were carried out as described in the text. Each ABC family member was included on the basis of identification by its ATP-binding domain and the inclusion of approximately 10 aa upstream and 120 aa downstream of this site. Some ABC proteins contain two ATP-binding sites. In these cases, each site was analyzed independently; the first site is depicted in by the continuous lines, and the second site by the broken lines. Sterolin forms a distinct family (bold solid lines), with its nearest neighbor being the White gene family, the mammalian homologues of which include ABC8 family members.