An Oligopeptide Transporter Gene Family in Arabidopsis

• Published in: Plant physiology (Bethesda) 2002-01, Vol.128 (1), p.21-29
• Main Authors: Koh, Serry, Amy M. Wiles, Joshua S. Sharp, Fred R. Naider, Becker, Jeffrey M., Stacey, Gary
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; AtOPT gene; Barley; Biological and medical sciences; Biological Transport; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell physiology; Cloning, Molecular; Complementary DNA; Flowers; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; Genes. Genome; Genome Analysis; Messenger RNA; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Multigene Family - genetics; Nitrogen; oligopeptide transporter; Oligopeptides - metabolism; Peptides; Phylogeny; Plant physiology and development; Plants; Plasma membrane and permeation; Recombinant Proteins - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Sequence Homology, Amino Acid; Yeasts
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.010332

We have identified nine oligopeptide transporter (OPT) orthologs (AtOPT1 to AtOPT9) in Arabidopsis. These proteins show significant sequence similarity to OPTs of Candida albicans (CaOpt1p), Schizosaccharomyces pombe (Isp4p), and Saccharomyces cerevisiae (Opt1p and Opt2p). Hydrophilicity plots of the OPTs suggest that they are integral membrane proteins with 12 to 14 transmembrane domains. Sequence comparisons showed that the AtOPTs form a distinct subfamily when compared with the fungal OPTs. Two highly conserved motifs (NPG and KIPPR) were found among all OPT members. The identification of multiple OPTs in Arabidopsis suggests that they may play different functional roles. This idea is supported by the fact that AtOPTs have a distinct, tissue-specific expression pattern. The cDNAs encoding seven of the AtOPTs were cloned into a yeast vector under the control of a constitutive promoter. AtOPT4 expressed in S. cerevisiae mediated the uptake of KLG-[3H]L. Similarly, expression of five of the seven AtOPT proteins expressed in yeast conferred the ability to uptake tetra- and pentapeptides as measured by growth. This study provides new evidence for multiple peptide transporter systems in Arabidopsis, suggesting an important physiological role for small peptides in plants.