Phylogenetic relationships of caveolin sequences inferred from a maximum-likelihood phylogeny. A maximum-likelihood phylogeny was inferred for representative caveolins from the current study (black) in combination with caveolin sequences previously analyzed by Kirkham et al. (2008). Previously analyzed caveolins are color-coded according to their classifications. Rooting was performed under the assumption that the choanoflagellate sequence constitutes an outgroup. Support values (percent replication in 1,000 rapid bootstrap pseudoreplicates) are shown for the major splits. Branch lengths are proportional to the average number of substitutions per site (refer to scale). Splits denoting the higher order relationship between the apparent Prot. G2, CAV3, CAV1, CAVY (ext.), Prot. G3, and CAV2/2R clades received extremely low bootstrap support and are therefore represented by a polytomy in the final tree. The asterisk, *, indicates a caveolin-related protein from S. rosetta.