Kinetic and phylogenetic analysis of plant polyamine uptake transporters.
The rice gene Polyamine Uptake Transporter1 (PUT1) was originally identified based on its homology to the polyamine uptake transporters LmPOT1 and TcPAT12 in Leishmania major and Trypanosoma cruzi, respectively. Here we show that five additional transporters from rice and Arabidopsis that cluster in the same clade as PUT1 all function as high affinity spermidine uptake transporters. Yeast expression assays of these genes confirmed that uptake of spermidine was minimally affected by 166 fold or greater concentrations of amino acids. Characterized polyamine transporters from both Arabidopsis thaliana and Oryza sativa along with the two polyamine transporters from L. major and T. cruzi were aligned and used to generate a hidden Markov model. This model was used to identify significant matches to proteins in other angiosperms, bryophytes, chlorophyta, discicristates, excavates, stramenopiles and amoebozoa. No significant matches were identified in fungal or metazoan genomes. Phylogenic analysis showed that some sequences from the haptophyte, Emiliania huxleyi, as well as sequences from oomycetes and diatoms clustered closer to sequences from plant genomes than from a homologous sequence in the red algal genome Galdieria sulphuraria, consistent with the hypothesis that these polyamine transporters were acquired by horizontal transfer from green algae. Leishmania and Trypansosoma formed a separate cluster with genes from other Discicristates and two Entamoeba species. We surmise that the genes in Entamoeba species were acquired by phagotrophy of Discicristates. In summary, phylogenetic and functional analysis has identified two clades of genes that are predictive of polyamine transport activity.
Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
Vaishali
V
Mulangi
Marcus C
MC
Chibucos
Vipaporn
V
Phuntumart
Paul F
PF
Morris
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D005816:Genetic Complementation Test; D007700:Kinetics; D018320:Leishmania major / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009928:Organ Specificity; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D011700:Putrescine / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013095:Spermidine / Q000378:metabolism; D013379:Substrate Specificity; D013997:Time Factors; D014349:Trypanosoma cruzi / Q000235:genetics / Q000378:metabolism
D027682:Cation Transport Proteins; D026901:Membrane Transport Proteins; C500804:POT1 protein, Leishmania major; D010940:Plant Proteins; D011073:Polyamines; D015800:Protozoan Proteins; D013095:Spermidine; D011700:Putrescine