Supplementary Information - Polypharmacology translates between species and phylogenetic distance

<p><span>Recently, we postulated the existence of ‘multitarget binding sites’, reoccurring structural motifs that interconnect otherwise structurally, functionally, and/or phylogenetically distant proteins. In this study, we functionally assessed a selection of multitarget ATP-binding cassette (pan-ABC) transporter modulators against zebrafish (<em>Danio rerio</em>) organic anion transporting polypeptide (drOatp1d1), a transport protein of the solute carrier (SLC) superfamily. Zebrafishes are important <em>in vivo</em> models in drug development to evaluate drug pharmacokinetics and pharmacodynamics. In total, 87.0% of the compounds were identified as drOatp1d1 transport inhibitors despite the relative phylogenetic distance of drOatp1d1 to other Oatps/OATPs. The observed effects resembled the ones observed for human OATP1A2, OATP1B1, OATP1B3, and OATP2B1, and potent hit molecules appeared to bind to a potential drOatp1d1 binding site derived from a OATP1B1 cryo-EM structure – strengthening the notion of common structural motifs between membrane transporters. The bioactivity of pranlukast (<strong>PRA</strong>) on human OATPs could be accurately predicted based on its activity on drOatp1d1.<strong> </strong>The collection of pan-ABC transporter modulators also showed activity against other zebrafish (<em>i.e.</em>, drAbcb4) and non-zebrafish (<em>i.e.</em>, murine Abca1) membrane transporters, ultimately rendering it a suitable tool to translate between species to tackle the undruggability of membrane transporters and potentially other proteins by addressing conserved structural motifs.</span></p>