PROF1 multiple sequence alignment. Multiple sequence alignment of all PROF1 receptors over a sequence range that includes TM domains I-IV (used for phylogenetic analysis). Residues are colored according to a conservation threshold set at 80% within each group. The locations of individual TM domains were approximated by alignment to Rhodopsin and are depicted above the MSA. Red asterisks are used to mark residue locations where the among-group PROF1 identity level threshold (> 80%) is met.