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Journal of Agricultural and Food... Jan 2019The objective of this study was to characterize the expression profile, transport kinetics, and regulation of peptide transporters in bovine mammary epithelial cells...
The objective of this study was to characterize the expression profile, transport kinetics, and regulation of peptide transporters in bovine mammary epithelial cells (BMECs). Quantitative reverse-transcription real-time PCR, Western blotting, and immunofluorescence staining were used to investigate the expression of peptide transporters in bovine mammary tissues. The effects of time, pH, concentration, and specific inhibitors on β-alanyl-l-lysyl- Nε-7-amino-4-methyl-coumarin-3-acetic acid (β-Ala-Lys-AMCA) uptake in BMECs were also studied. The results showed that the peptide transporters PepT2 and PhT1 are both expressed in bovine mammary glands. The optimal pH for the uptake of β-Ala-Lys-AMCA in BMECs was 6.5. The transport-kinetics study suggested that the uptake of β-Ala-Lys-AMCA in BMECs is saturable over the tested concentration, with a K value of 82 ± 18 μM and a V of 124 ± 11 pmol/min per milligram of protein. Other dipeptides, including Gly-Sar, Met-Gly, and Met-Met, competitively inhibited β-Ala-Lys-AMCA uptake in BMECs. However, histidine had no effect on β-Ala-Lys-AMCA uptake. Furthermore, knocking down PepT2 could significantly reduce β-Ala-Lys-AMCA uptake, but PhT1 interference had no effect on peptide uptake in BMECs. The inhibition of PI3K and Akt decreased the uptake of β-Ala-Lys-AMCA. The above results revealed functional characteristics of peptide transporters and demonstrated that PepT2 may play a major role in β-Ala-Lys-AMCA uptake in BMECs. Moreover, the PI3K-Akt signaling pathway may regulate the uptake of β-Ala-Lys-AMCA in BMECs.
Topics: Animals; Biological Transport; Cattle; Epithelial Cells; Female; Kinetics; Mammary Glands, Animal; Membrane Transport Proteins; Peptides
PubMed: 30525553
DOI: 10.1021/acs.jafc.8b05637 -
Journal of General Microbiology Sep 1984Aminoxy analogues of di- and tripeptides in which the peptide linkage is replaced by -CO-NHO-, either as an L- or D-2-aminoxypropionic acid (L or D-OAla) residue, have...
Aminoxy analogues of di- and tripeptides in which the peptide linkage is replaced by -CO-NHO-, either as an L- or D-2-aminoxypropionic acid (L or D-OAla) residue, have been examined for antibacterial activity in vitro and for uptake into Escherichia coli. Isolation of analogue-resistant mutants and cross-resistance tests with peptide-transport mutants indicate that all three peptide permeases can transport these backbone-modified analogues. A number of mutants with defects in particular intracellular peptidases show decreased sensitivity to a range of these analogues, allowing identification of the enzymes responsible for their cleavage and confirming that hydrolysis is essential for their toxicity. Ala-OAla is a bacteriostatic agent that inhibits nucleic acid and protein synthesis within 1 min of being added to an exponentially growing culture. In crude extracts Ala-OAla inhibits transaminase activity but only after liberation of OAla by endogenous peptidases. These antibacterial agents illustrate an approach to drug targeting in which peptide carriers are used to promote uptake of essentially impermeant toxic moieties.
Topics: Alanine; Anti-Bacterial Agents; Biological Transport; Escherichia coli; Hydrolysis; Membrane Transport Proteins; Peptide Hydrolases; Peptides; Salmonella typhimurium
PubMed: 6389761
DOI: 10.1099/00221287-130-9-2253 -
Proceedings of the National Academy of... Mar 2023Adenosine triphosphate-binding cassette (ABC) transporters, such as multidrug resistance protein 1 (MRP1), protect against cellular toxicity by exporting xenobiotic...
Adenosine triphosphate-binding cassette (ABC) transporters, such as multidrug resistance protein 1 (MRP1), protect against cellular toxicity by exporting xenobiotic compounds across the plasma membrane. However, constitutive MRP1 function hinders drug delivery across the blood-brain barrier, and MRP1 overexpression in certain cancers leads to acquired multidrug resistance and chemotherapy failure. Small-molecule inhibitors have the potential to block substrate transport, but few show specificity for MRP1. Here we identify a macrocyclic peptide, named CPI1, which inhibits MRP1 with nanomolar potency but shows minimal inhibition of a related multidrug transporter P-glycoprotein. A cryoelectron microscopy (cryo-EM) structure at 3.27 Å resolution shows that CPI1 binds MRP1 at the same location as the physiological substrate leukotriene C4 (LTC). Residues that interact with both ligands contain large, flexible sidechains that can form a variety of interactions, revealing how MRP1 recognizes multiple structurally unrelated molecules. CPI1 binding prevents the conformational changes necessary for adenosine triphosphate (ATP) hydrolysis and substrate transport, suggesting it may have potential as a therapeutic candidate.
Topics: Adenosine Triphosphate; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP-Binding Cassette Transporters; Biological Transport; Cryoelectron Microscopy; Leukotriene C4; Multidrug Resistance-Associated Proteins; Peptides; Peptides, Cyclic
PubMed: 36893260
DOI: 10.1073/pnas.2220012120 -
Bulletin of Experimental Biology and... Feb 2011Dendrimers are a new class of nonviral vectors for gene or drug transport. Dendrimer capacity to penetrate through the blood-brain barrier remaines little studied....
Dendrimers are a new class of nonviral vectors for gene or drug transport. Dendrimer capacity to penetrate through the blood-brain barrier remaines little studied. Biotinylated polylysine dendrimer D5, similarly to human growth hormone biotinylated fragment covalently bound to D5 dendrimer, penetrates through the blood-brain barrier and accumulates in Drosophila brain after injection into the abdomen. Hence, D5 dendrimer can serve as a vector for peptide transport to brain cells.
Topics: Animals; Biological Transport, Active; Blood-Brain Barrier; Brain; Dendrimers; Drosophila melanogaster; Membrane Transport Proteins; Polylysine
PubMed: 22268035
DOI: 10.1007/s10517-011-1160-z -
Ciba Foundation Symposium 1971
Topics: Amino Acids; Biological Transport, Active; Cell Membrane; Diffusion; Dipeptides; Escherichia coli; Hydrolysis; Membrane Transport Proteins; Mutation; Oligopeptides; Peptides; Protein Binding; Protein Conformation; Stereoisomerism; Structure-Activity Relationship; Temperature; Time Factors; Tritium
PubMed: 4949894
DOI: 10.1002/9780470719879.ch3 -
Expert Opinion on Drug Delivery 2016Over the past years, a significant number of papers have substantiated earlier findings proposing a role for drug transporter proteins in pulmonary drug disposition.... (Review)
Review
INTRODUCTION
Over the past years, a significant number of papers have substantiated earlier findings proposing a role for drug transporter proteins in pulmonary drug disposition. Whilst the majority of reports present data from in vitro models, a growing number of publications advance the field by introducing sophisticated ex vivo and in vivo techniques. In a few cases, evidence from clinical studies in human volunteers is complementing the picture.
AREAS COVERED
In this review, recent advances in pulmonary drug transporter research are critically evaluated. Transporter expression data in tissues and cell-based in vitro models is summarized and information on transport activity assessed. Novel techniques allowing for better quantification of transporter-related effects following pulmonary delivery are also described.
EXPERT OPINION
Different tissue and cell populations of the lung have distinct transporter expression patterns. Whether these patterns are affected by disease, gender and smoking habits requires further clarification. Transporters have been found to have an impact on drug absorption processes, at least in vitro. Recent ex vivo experiments using isolated, perfused lung models, however, suggest that mainly efflux pumps have significant effects on absorption into the pulmonary circulation. Whether these rodent-based ex vivo models predict the human situation is basis for further research.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Biological Transport; Drug Delivery Systems; Humans; Lung; Membrane Transport Proteins; Mucous Membrane; Multidrug Resistance-Associated Proteins; Neoplasm Proteins; Organic Cation Transport Proteins; Pharmaceutical Preparations
PubMed: 26909544
DOI: 10.1517/17425247.2016.1140144 -
Biochimica Et Biophysica Acta Jan 2009The mitochondrial inner membrane has a central function for the energy metabolism of the cell. The respiratory chain generates a proton gradient across the inner... (Review)
Review
The mitochondrial inner membrane has a central function for the energy metabolism of the cell. The respiratory chain generates a proton gradient across the inner mitochondrial membrane, which is used to produce ATP by the F1Fo-ATPase. To maintain the electrochemical gradient, the inner membrane represents an efficient permeability barrier for small molecules. Nevertheless, metabolites as well as polypeptide chains need to be transported across the inner membrane while the electrochemical gradient is retained. While specialized metabolite carrier proteins mediate the transport of small molecules, dedicated protein translocation machineries in the inner mitochondrial membrane (so called TIM complexes) transport precursor proteins across the inner membrane. Here we describe the organization of the TIM complexes and discuss the current models as to how they mediate the posttranslational import of proteins across and into the inner mitochondrial membrane.
Topics: Animals; Biological Transport; Carrier Proteins; Humans; Intracellular Signaling Peptides and Proteins; Mitochondrial Membrane Transport Proteins; Mitochondrial Membranes; Mitochondrial Proteins; Mitochondrial Proton-Translocating ATPases; Models, Biological; Protein Precursors; Protein Subunits; Protein Transport
PubMed: 18590776
DOI: 10.1016/j.bbamcr.2008.05.026 -
Biological Chemistry Aug 2009A large and dynamic membrane-associated machinery orchestrates the translocation of antigenic peptides into the endoplasmic reticulum (ER) lumen for subsequent loading... (Review)
Review
A large and dynamic membrane-associated machinery orchestrates the translocation of antigenic peptides into the endoplasmic reticulum (ER) lumen for subsequent loading onto major histocompatibility complex (MHC) class I molecules. The peptide-loading complex ensures that only high-affinity peptides, which guarantee long-term stability of MHC I complexes, are presented to T-lymphocytes. Adaptive immunity is dependent on surface display of the cellular proteome in the form of protein fragments, thus allowing efficient recognition of infected or malignant transformed cells. In this review, we summarize recent findings of antigen translocation by the transporter associated with antigen processing and loading of MHC class I molecules in the ER, focusing on the mechanisms involved in this process.
Topics: ATP Binding Cassette Transporter, Subfamily B, Member 2; ATP Binding Cassette Transporter, Subfamily B, Member 3; ATP-Binding Cassette Transporters; Animals; Antigen Presentation; Endoplasmic Reticulum; Histocompatibility Antigens Class I; Humans; Membrane Transport Proteins; Models, Immunological; Models, Molecular; Peptides; Protein Transport; T-Lymphocytes
PubMed: 19426129
DOI: 10.1515/BC.2009.069 -
Cellular and Molecular Life Sciences :... May 2000The cotransport of protons and peptides is now recognised as a major route by which dietary nitrogen is absorbed from the intestine, and filtered protein reabsorbed in... (Review)
Review
The cotransport of protons and peptides is now recognised as a major route by which dietary nitrogen is absorbed from the intestine, and filtered protein reabsorbed in the kidney. Recently, molecular biology has had a very substantial impact on the study of peptide transport, and here we review the molecular and functional information available within the framework of physiology. To this end we consider not only the mammalian peptide transporters and their tissue distribution and regulation but also those from other species (including Caenorhabditis elegans) which make up the proton-dependent oligopeptide transport superfamily. In addition, understanding the binding requirements for transported substrates may allow future design and targeted tissue delivery of peptide and peptidomimetic drugs. Finally, we aim to highlight some of the less well understood areas of peptide transport, in the hope that it will stimulate further research into this challenging yet exciting topic.
Topics: Amino Acid Sequence; Animals; Binding Sites; Biological Transport, Active; Caenorhabditis elegans; Carrier Proteins; Female; Genome; Hormones; Humans; Molecular Sequence Data; Peptide Transporter 1; Peptides; Pregnancy; Second Messenger Systems; Sequence Homology, Amino Acid; Symporters; Tissue Distribution
PubMed: 10892342
DOI: 10.1007/s000180050040 -
Pharmaceutical Research Nov 2023The oligopeptide/histidine transporters PHT1 and PHT2, two mammalian solute carrier family 15A proteins, mediate the transmembrane transport of histidine and some... (Review)
Review
The oligopeptide/histidine transporters PHT1 and PHT2, two mammalian solute carrier family 15A proteins, mediate the transmembrane transport of histidine and some di/tripeptides via proton gradient. PHT1 and PHT2 are distributed in a variety of tissues but are preferentially expressed in immune cells and localize to the lysosome-related organelles. Studies have reported the relationships between PHT1/PHT2 and immune diseases. PHT1 and PHT2 participate in the regulation of lysosomal homeostasis and lysosome-associated signaling pathways through their transport and nontransport functions, playing important roles in inflammatory diseases. In this review, we summarize recent research on PHT1 and PHT2, aiming to provide reference for their further biological research and as targets for drug design.
Topics: Animals; Biological Transport; Histidine; Mammals; Membrane Transport Proteins; Oligopeptides; Symporters
PubMed: 37610621
DOI: 10.1007/s11095-023-03589-8