Minimal Molecular Determinants of Substrates for Recognition by the Intestinal Peptide Transporter

Döring, Frank; Will, Jutta; Amasheh, Salah; Clauss, Wolfgang; Ahlbrecht, H.; Daniel, Hannelore

doi:10.1074/jbc.273.36.23211

Cited by 135 publications

(97 citation statements)

References 24 publications

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“…Mucus retention in the CF specimens, however, reduced the uptake of the reporter molecule quantitatively. Together with recent information on the minimal molecular requirements of substrates for recognition by peptide transporters, 44 our findings provide new insights into pulmonary transport pathways and peptide metabolism and the perspectives of optimising drug treatment by targeting a potent membrane transport protein. …”

Section: Discussionmentioning

confidence: 66%

Distribution and function of the peptide transporter PEPT2 in normal and cystic fibrosis human lung

Groneberg

Eynott²,

Döring³

et al. 2002

Thorax

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Background: Aerosol administration of peptide based drugs has an important role in the treatment of various pulmonary and systemic diseases. The characterisation of pulmonary peptide transport pathways can lead to new strategies in aerosol drug treatment. Methods: Immunohistochemistry and ex vivo uptake studies were established to assess the distribution and activity of the β-lactam transporting high affinity proton coupled peptide transporter PEPT2 in normal and cystic fibrosis human airway tissue. Results: PEPT2 immunoreactivity in normal human airways was localised to cells of the tracheal and bronchial epithelium and the endothelium of small vessels. In peripheral lung immunoreactivity was restricted to type II pneumocytes. In sections of cystic fibrosis lung a similar pattern of distribution was obtained with signals localised to endothelial cells, airway epithelium, and type II pneumocytes. Functional ex vivo uptake studies with fresh lung specimens led to an uptake of the fluorophore conjugated dipeptide derivative D-Ala-L-Lys-AMCA into bronchial epithelial cells and type II pneumocytes. This uptake was competitively inhibited by dipeptides and cephalosporins but not ACE inhibitors, indicating a substrate specificity as described for PEPT2. Conclusions: These findings provide evidence for the expression and function of the peptide transporter PEPT2 in the normal and cystic fibrosis human respiratory tract and suggest that PEPT2 is likely to play a role in the transport of pulmonary peptides and peptidomimetics.

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Section: Discussionmentioning

confidence: 66%

Distribution and function of the peptide transporter PEPT2 in normal and cystic fibrosis human lung

Groneberg

Eynott²,

Döring³

et al. 2002

Thorax

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“…In mammals, 7-aminoheptanoic acid and 8-aminocaprylic acid are not transported by members of the GAT family. 5 The proton-coupled animal peptide transporter PepT1 does not recognize GABA but transports both 5-aminovaleric acid and 6-aminocaproic acid, and even 8-aminocaprylic acid and 11-amino-undecanoic acid were recognized (51). However, these long chain -aminofatty acids are not substrates for other peptide transporters (i.e.…”

Section: Discussionmentioning

confidence: 99%

AtGAT1, a High Affinity Transporter for γ-Aminobutyric Acid in Arabidopsis thaliana

Meyer

Eskandari

Grallath

et al. 2006

Journal of Biological Chemistry

133

112

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Functional characterization of Arabidopsis thaliana GAT1 in heterologous expression systems, i.e. Saccharomyces cerevisiae and Xenopus laevis oocytes, revealed that AtGAT1 (At1g08230) codes for an H ؉ -driven, high affinity ␥-aminobutyric acid (GABA) transporter. In addition to GABA, other -aminofatty acids and butylamine are recognized. In contrast to the most closely related proteins of the proline transporter family, proline and glycine betaine are not transported by AtGAT1. AtGAT1 does not share sequence similarity with any of the non-plant GABA transporters described so far, and analyses of substrate selectivity and kinetic properties showed that AtGAT1-mediated transport is similar but distinct from that of mammalian, bacterial, and S. cerevisiae GABA transporters. Consistent with a role in GABA uptake into cells, transient expression of AtGAT1/green fluorescent protein fusion proteins in tobacco protoplasts revealed localization at the plasma membrane. In planta, AtGAT1 expression was highest in flowers and under conditions of elevated GABA concentrations such as wounding or senescence. ␥-Aminobutyric acid (GABA)3 is a four-carbon non-protein amino acid present in prokaryotes and eukaryotes. Although GABA was discovered in 1949 as a constituent of potato tubers, research on GABA metabolism and transport advanced much faster in the animal system as GABA turned out to be the most abundant inhibitory neurotransmitter in the central nervous system (1). Uptake of GABA into neurons and glia has been investigated in detail and shown to be mediated by Na ϩ -dependent and Cl Ϫ -facilitated GABA transporters (GATs), thus regulating concentration and duration of the neurotransmitter GABA in the synapse (2, 3). In addition to its function as a neurotransmitter, GABA plays a role in the development of the nervous system, influencing proliferation, migration, and differentiation (4). With the exception of the general amino acid permease Bra RI from Rhizobium leguminosarum, which belongs to the ATP binding cassette (ABC) transporters, GABA uptake in Gram-negative and Gram-positive bacteria as well as in Saccharomyces cerevisiae is mediated by members of the APC (amino acid/polyamine/organocation) superfamily of transporters (5, 6). In both bacteria and yeast, GABA uptake and biosynthesis are mainly involved in nitrogen and carbon metabolism (7-9), although other functions such as GABA synthesis for pH regulation in Escherichia coli and for normal oxidative stress tolerance in S. cerevisiae have also been postulated (10, 11).Much less is known about the role of GABA and its transport across the plasma membrane in plants. GABA rapidly accumulates under various stress conditions such as low temperature, mechanical stimulation, and oxygen deficiency (12, 13). As in other organisms, GABA is synthesized in plants primarily by decarboxylation of glutamate and degraded via succinic semialdehyde to succinate, a pathway that is also called the GABA shunt (12). Alternatively, succinic semialdehyde can be further catabolized to ␥-h...

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“…Large sets of dipeptides, amino acid derivatives, or peptidomimetics have been probed for transport in competition experiments utilizing cells expressing either one of the transporters, by the measurement of substrate-mediated transport currents in Xenopus laevis oocytes expressing PEPT1 or PEPT2, or by competition experiments in the yeast Pichia pastoris heterologously expressing either one of the mammalian transporters (11,12,14,21,22,66,67). One important finding for understanding the "multispecificity" of the peptide transporters was that neither PEPT1 nor PEPT2 requires a peptide bond in a substrate and that the minimal structural requirement in a substrate for binding and transport is a simple carbon chain that separates the oppositely charged NH 2 and COOH head groups by an intramolecular distance of Ͼ 500 Ͻ 630 picometers (21). In the case of PEPT2, we recently showed by the rational design of a large set of test compounds that the much higher affinity of PEPT2 for the same substrates is based on the requirement of an additional carbonyl function, but After 30 min, a 10-min kidney perfusion with ice-cold unlabeled minimal essential media was performed, followed by perfusion fixation with freshly prepared 4% paraformaldehyde (PFA) in PBS at pH 7.4 for 5 min.…”

Section: The Substrate Specificity Of Pept1 and Pept2mentioning

confidence: 99%

An update on renal peptide transporters

Daniel

Rubio‐Aliaga

2003

American Journal of Physiology-Renal Physiology

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Daniel, Hannelore, and Isabel Rubio-Aliaga. An update on renal peptide transporters. Am J Physiol Renal Physiol 284: F885-F892, 2003; 10.1152/ajprenal.00123.2002The brush-border membrane of renal epithelial cells contains PEPT1 and PEPT2 proteins that are rheogenic carriers for short-chain peptides. The carrier proteins display a distinct surface expression pattern along the proximal tubule, suggesting that initially di-and tripeptides, either filtered or released by surface-bound hydrolases from larger oligopeptides, are taken up by the low-affinity but high-capacity PEPT1 transporter and then by PEPT2, which possesses a higher affinity but lower transport capacity. Both carriers transport essentially all possible di-and tripeptides and numerous structurally related drugs. A unique feature of the mammalian peptide transporters is the capability of proton-dependent electrogenic cotransport of all substrates, regardless of their charge, that is achieved by variable coupling in proton movement along with the substrate down the transmembrane potential difference. This review focuses on the postcloning research efforts to understand the molecular physiology of peptide transport processes in renal tubules and summarizes available data on the underlying genes, protein structures, and transporter function as derived from studies in heterologous expression systems. PEPT1; PEPT2; renal physiology; localization; functional analysis RENAL TUBULAR PEPTIDE TRANSPORT activity was originally discovered after intravenous infusion of the resistant dipeptide Gly-Sar in rats that resulted in a high accumulation of the intact dipeptide in renal tissue (1, 3). Studies with renal brush-border membrane vesicles established that renal apical peptide uptake was an electrogenic, proton-dependent uphill transport process for di-and tripeptides and related drugs mediated by two kinetically different systems (for a review, see Ref. 38). The underlying proteins, differing in transport characteristics, now designated as PEPT1 (SLC15A1) and PEPT2 (SLC15A2), have been identified, and the corresponding genes have been cloned from a variety of species (10,24,25,39,41,(52)(53)(54). The transporters have been expressed in various cellular models, and information on structure, transport function, and regulation has been gathered by flux studies and electrophysiological techniques. Expression analysis of transporter mRNA and protein by in situ hybridization and immunohistochemistry has extended our knowledge of tissue distribution, particularly the renal zonation of PEPT1 and PEPT2 surface expression. THE MOLECULAR ENTITIES OF APICAL PEPTIDE TRANSPORTPEPT1 and PEPT2 are polytopic integral membrane proteins with 12 predicted membrane-spanning domains and NH 2 -and COOH-terminal ends facing the cytosol. Transporter architecture and membrane topology have not been studied systematically, and therefore structural information is still mainly based on hydropathic analysis of amino acid sequences. The mammalian PEPT1 proteins comprise 701-710 amino acids, ...

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Minimal Molecular Determinants of Substrates for Recognition by the Intestinal Peptide Transporter

Cited by 135 publications

References 24 publications

Distribution and function of the peptide transporter PEPT2 in normal and cystic fibrosis human lung

Distribution and function of the peptide transporter PEPT2 in normal and cystic fibrosis human lung

AtGAT1, a High Affinity Transporter for γ-Aminobutyric Acid in Arabidopsis thaliana

An update on renal peptide transporters

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