Stimulation of Na+/Cl−-coupled Opioid Peptide Transport System in SK-N-SH Cells by L-kyotorphin, an Endogenous Substrate for H+-coupled Peptide Transporter PEPT2

2008 ◽  
Vol 23 (4) ◽  
pp. 254-262 ◽  
Author(s):  
Santoshanand V. Thakkar ◽  
Seiji Miyauchi ◽  
Puttur D. Prasad ◽  
Vadivel Ganapathy
Keyword(s):  
Transport System ◽  
Opioid Peptide ◽  
Peptide Transport ◽  
Peptide Transporter ◽  
Endogenous Substrate ◽  
Stimulation Of

scholarly journals Isolation of Peptide Transport System-6 from Brain Endothelial Cells: Therapeutic Effects with Antisense Inhibition in Alzheimer and Stroke Models

2008 ◽  
Vol 29 (2) ◽  
pp. 411-422 ◽  
Author(s):  
Dilek Dogrukol-Ak ◽  
Vijaya B Kumar ◽  
Jan S Ryerse ◽  
Susan A Farr ◽  
Sulekha Verma ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Transport System ◽  
Efflux Pumps ◽  
Peptide Transport ◽  
Peptide Transporter ◽  
Therapeutic Effects ◽  
Brain Uptake ◽  
Model Of Alzheimer’S Disease ◽  
Stroke Models

By isolating for the first time ever a peptide transporter from the blood—brain barrier (BBB) and developing an antisense that selectively targets the brain-to-blood efflux component, we were able to deliver a therapeutic concentration of the neurotrophic peptide pituitary adenylate cyclase-activating polypeptide (PACAP) 27 to brain in animal models of Alzheimer's and stroke. Efflux pumps at the BBB are major causes of BBB impermeability to peptides. PACAP is neuroprotective in vitro in femtomole amounts, but brain uptake of PACAP27 is limited by an efflux component of peptide transport system-6 (PTS-6). Here, we characterized, isolated, and sequenced this component of PTS-6, identifying it as β-F1 ATPase, and colocalized it with PACAP27 on BBB endothelial cells. Antisenses targeting the BBB inhibited PACAP27 efflux, thus increasing brain uptake of PACAP27. Treatment with antisense +PACAP27 improved cognition in a mouse model of Alzheimer's disease and reduced infarct size after cerebral ischemia. This represents the first isolation from BBB tissue of a peptide transporter and shows that inhibition of peptide efflux pumps is a potential strategy for drug delivery to brain.

Differential Modulation of Sodium- and Chloride-Dependent Opioid Peptide Transport System by Small Nonopioid Peptides and Free Amino Acids

2007 ◽  
Vol 321 (1) ◽  
pp. 257-264 ◽  
Author(s):  
Seiji Miyauchi ◽  
Elangovan Gopal ◽  
Santosh V. Thakkar ◽  
Satoshi Ichikawa ◽  
Puttur D. Prasad ◽  
...  
Keyword(s):  
Amino Acids ◽  
Transport System ◽  
Free Amino Acids ◽  
Free Amino ◽  
Opioid Peptide ◽  
Peptide Transport ◽  
Differential Modulation

Towards a structural understanding of drug and peptide transport within the proton-dependent oligopeptide transporter (POT) family

2011 ◽  
Vol 39 (5) ◽  
pp. 1353-1358 ◽  
Author(s):  
Simon Newstead
Keyword(s):  
High Resolution ◽  
Anticancer Agents ◽  
Targeted Delivery ◽  
Drug Transport ◽  
Structural Information ◽  
Sequence Similarity ◽  
The Body ◽  
Peptide Transport ◽  
Peptide Transporter ◽  
Starting Point

One of the principal aims of modern drug design is the targeted delivery of drugs within the body, such as to the central nervous system, combined with their exclusion from the liver and kidneys, which break down foreign molecules and subsequently eliminate them. Many of the commonly prescribed drugs are transported into cells and across the plasma membrane via endogenous membrane transporters, whose principal roles are the uptake of essential nutrients for metabolism. In many cases, such drug transport is serendipitous as they are simply mistaken as ‘natural’ compounds. Many of these transporters could, however, be targeted more efficiently, improving drug absorption, distribution and retention. The molecular details of these drug–transporter interactions, however, are at best poorly understood, in large part through the absence of any high-resolution structural information. To address this issue, we recently determined the structure of a prokaryotic peptide transporter, PepTSo from Shewanella oneidensis, which shares a high degree of sequence similarity and functional characteristics with the human PepT1 and PepT2 proteins. PepT1 and PepT2 contribute significantly to the oral bioavailability and pharmacokinetic properties of a number of important drug families, including antibiotics, antivirals and anticancer agents. The crystal structure of PepTSo provides the first high-resolution model of a drug importer and provides the starting point for understanding drug and peptide transport within the human body.

scholarly journals Glycans in the intestinal peptide transporter PEPT1 contribute to function and protect from proteolysis

2017 ◽  
Vol 312 (6) ◽  
pp. G580-G591 ◽  
Author(s):  
Tamara Stelzl ◽  
Kerstin E. Geillinger-Kästle ◽  
Jürgen Stolz ◽  
Hannelore Daniel
Keyword(s):  
Protein Function ◽  
Proteolytic Cleavage ◽  
Glycosylation Site ◽  
Proteinase K ◽  
Peptide Transport ◽  
Peptide Transporter ◽  
Electrophysiological Recordings ◽  
Transport Velocity ◽  
Flux Measurements ◽  
The Individual

Despite the fact that many membrane proteins carry extracellular glycans, little is known about whether the glycan chains also affect protein function. We recently demonstrated that the proton-coupled oligopeptide transporter 1 (PEPT1) in the intestine is glycosylated at six asparagine residues (N50, N406, N439, N510, N515, and N532). Mutagenesis-induced disruption of the individual N-glycosylation site N50, which is highly conserved among mammals, was detected to significantly enhance the PEPT1-mediated inward transport of peptides. Here, we show that for the murine protein the inhibition of glycosylation at sequon N50 by substituting N50 with glutamine, lysine, or cysteine or by replacing S52 with alanine equally altered PEPT1 transport kinetics in oocytes. Furthermore, we provide evidence that the uptake of [14C]glycyl-sarcosine in immortalized murine small intestinal (MODE-K) or colonic epithelial (PTK-6) cells stably expressing the PEPT1 transporter N50Q is also significantly increased relative to the wild-type protein. By using electrophysiological recordings and tracer flux studies, we further demonstrate that the rise in transport velocity observed for PEPT1 N50Q is bidirectional. In line with these findings, we show that attachment of biotin derivatives, comparable in weight with two to four monosaccharides, to the PEPT1 N50C transporter slows down the transport velocity. In addition, our experiments provide strong evidence that glycosylation of PEPT1 confers resistance against proteolytic cleavage by proteinase K, whereas a remarkable intrinsic stability against trypsin, even in the absence of N-linked glycans, was detected. NEW & NOTEWORTHY This study highlights the role of N50-linked glycans in modulating the bidirectional transport activity of the murine peptide transporter PEPT1. Electrophysiological and tracer flux measurements in Xenopus oocytes have shown that removal of the N50 glycans increases the maximal peptide transport rate in the inward and outward directions. This effect could be largely reversed by replacement of N50 glycans with structurally dissimilar biotin derivatives. In addition, N-glycans were detected to stabilize PEPT1 against proteolytic cleavage.

Regulation of paracellular permeability in Caco-2 cell monolayers by protein kinase C

1993 ◽  
Vol 265 (5) ◽  
pp. G955-G962 ◽  
Author(s):  
W. F. Stenson ◽  
R. A. Easom ◽  
T. E. Riehl ◽  
J. Turk
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Myristate Acetate ◽  
Paracellular Permeability ◽  
Colonic Adenocarcinoma ◽  
Myristate Acetate ◽  
Cell Monolayers ◽  
Kinase C ◽  
Endogenous Substrate ◽  
Stimulation Of

Caco-2 cells are an enterocyte-like cell line derived from a human colonic adenocarcinoma. Paracellular permeability was assessed in monolayers of these cells by transmonolayer resistance and by the permeation of [3H]mannitol across the monolayer. Paracellular permeability was increased by the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (50 nM), carbachol (500 microM), and the combination of carbachol (50 microM) and monolein (100 microM), an inhibitor of diacylglycerol kinase, as manifested by a decrease in transmonolayer resistance and an increase in mannitol permeation. The effects of all of these stimuli on transmonolayer resistance were inhibited by staurosporine (3 nM), an inhibitor of PKC. The effects of carbachol plus monolein were also inhibited by atropine (0.1 microM), a muscarinic antagonist. Treatment of the monolayers with each of the stimuli was associated with translocation of PKC activity from cytosol to a membrane-associated state. Stimulation of Caco-2 cell monolayers with phorbol myristate acetate or with the combination of carbachol and monolein was also associated with phosphorylation of the MARCKS protein, an endogenous substrate of PKC. These data support the hypothesis that intestinal paracellular permeability is regulated by the activity of enterocyte PKC and demonstrate that the increase in paracellular permeability induced by binding of carbachol to the muscarinic receptor is mediated by activation of PKC.

Stimulation of the ionic transport system in Brassica napus by a plant growth-promoting rhizobacterium (Achromobacter sp.)

2000 ◽  
Vol 46 (3) ◽  
pp. 229-236 ◽  
Author(s):  
H. Bertrand ◽  
C. Plassard ◽  
X. Pinochet ◽  
B. Touraine ◽  
P. Normand ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Plant Growth ◽  
Transport System ◽  
Ionic Transport ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Stimulation Of

A characterisation of the peptide transport system in barley seeds

1995 ◽  
Vol 23 (4) ◽  
pp. 558S-558S ◽  
Author(s):  
WANDA M. WATERWORTH ◽  
CHRIS E. WEST ◽  
DAVID J. HARDY ◽  
CLIFFORD M. BRAY
Keyword(s):  
Transport System ◽  
Peptide Transport
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