Functional linkage of H+/peptide transporter PEPT2 and Na+/H+ exchanger in primary cultures of astrocytes from mouse cerebral cortex

Wada, Mayuko; Miyakawa, Sakiko; Shimada, Ayumi; Okada, Naoki; Yamamoto, Akira; Fujita, Takuya

doi:10.1016/j.brainres.2005.02.064

Cited by 32 publications

(24 citation statements)

References 42 publications

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“…This coupling might provide PEPT2 with a sufficient proton gradient. In fact, functional linkage of PEPT2 and NHE1 and/or NHE2 has been described in primary cultures of astrocytes to permit optimal uptake of dipeptides [56]. This model is supported by our data that demonstrate that PEPT2 becomes partially sodium dependent upon coexpression of NHE3.…”

Section: Discussionsupporting

confidence: 79%

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The Peptide Transporter PEPT2 is Targeted by the Protein Kinase SGK1 and the Scaffold Protein NHERF2

Boehmer

Palmada

Fabian

et al. 2008

Cell Physiol Biochem

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PEPT1 and PEPT2 are members of the family of proton-dependent oligopeptide transporters that mediate electrogenic uphill transport of small peptides and peptidomimetics into a variety of cells. Kinetic properties and substrate recognition sites of those transporters have been well defined previously. Little is known, however, about regulation of those transporters. Both PEPT isoforms contain putative phosphorylation sites for the serum and glucocorticoid inducible kinase SGK1 and a C-terminal PDZ binding motif that might be recognized by PDZ domains of the Na⁺/H⁺ exchanger regulatory factors NHERF1 and NHERF2. Thus, the present study attempted to clarify the role of SGK1 and NHERFs in the modulation of PEPT isoforms. Expression studies in Xenopus oocytes with subsequent electrophysiology and immunoassays revealed that SGK1 and NHERF2, but not the NHERF1 isoform specifically enhance PEPT2 function and surface abundance. The kinase is effective through phosphorylation of ¹⁸⁵Ser within the SGK1 consensus site, since disruption of this site prevented transporter modulation by the kinase. NHERF2 failed to regulate the C-terminal deletion mutant (PEPT2ΔC) indicating that the C-terminal PDZ-binding motif in PEPT2 governs transport modulation by NHERF2. Coexpression of NHE3 stimulates PEPT2 activity to a similar extent as coexpression of NHERF2. Dynasore experiments demonstrated that SGK1 and NHERF2 activate PEPT2 by stabilizing the transporter at the cell surface. In conclusion, the present results reveal two novel PEPT2 posttranslational modulators, SGK1 and NHERF2, which might regulate transport of oligopeptides and peptidomimetic drugs.

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Section: Discussionsupporting

confidence: 79%

“…A functional interaction between peptide transporters and the sodium proton exchanger NHE has been described earlier [56]. To investigate if PEPT2 is upregulated by NHE3 in the Xenopus oocyte expression system we coexpressed both proteins with or without the NHERF2 scaffold protein.…”

Section: S422dmentioning

confidence: 99%

The Peptide Transporter PEPT2 is Targeted by the Protein Kinase SGK1 and the Scaffold Protein NHERF2

Boehmer

Palmada

Fabian

et al. 2008

Cell Physiol Biochem

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“…Our results support the hypothesis (Sakata et al, 2001;Ocheltree et al, 2003;Wada et al, 2005;Bhardwaj et al, 2006;Lee et al, 2009) that PHT1 is located on the membrane of intracellular organelles, such as lysosomes and early endosomes. Although further studies are required to define the function of PHT1 in the thyroid epithelial cells, at least in theory this peptide/histidine transporter in the lysosomal membrane of thyrocytes could be important for the lysosome-to-cytosol release of short chain peptides as end products of Tg degradation.…”

supporting

confidence: 91%

“…This evidence would suggest intracellular localization of PHT1. In this respect, recent findings support the idea that PHT1, as well as PHT2, is localized in the lysosomal and/or early endosomal membranes (Sakata et al, 2001;Wada et al, 2005;Lee et al, 2009). However, because no data are available on the transport of Ala-Lys-AMCA by PHT1, we cannot exclude that PHT1 is expressed on the plasma membrane of PC Cl3 cells without participating to the uptake of the fluorescent substrate.…”

Section: Rt-pcr Experiments Confirmed Expression Of Pept2 In Pc Cl3 Csupporting

confidence: 71%

Functional expression of SLC15 peptide transporters in rat thyroid follicular cells

Romano

Barca²,

Kottra³

et al. 2010

Molecular and Cellular Endocrinology

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International audiencePeptide transport and expression of SoLute Carrier 15 (SLC15) peptide transporters was assessed in rat thyroid tissue and a rat thyroid cell line (PC Cl3 cells). Peptide transport was studied by monitoring the uptake of the fluorophore-conjugated dipeptide β-Ala-Lys-N-7-amino-4-methyl-coumarin-3-acetic acid (Ala-Lys-AMCA). Expression of SLC15-specific mRNA transcripts was analyzed by RT-PCR. Of the two SLC15 transporters expressed in thyroid follicular cells, namely PEPT2 (SLC15A2) and PHT1 (SLC15A4), only PEPT2 was involved in peptide transport at the plasma membrane, with PHT1 most likely being intracellular. Interestingly, at the mRNA level PEPT2 was up-regulated under TSH stimulation. These findings represent the first evidence that peptide transport occurs in thyroid follicular cells. SLC15 transporters could participate to recycling of peptides derived from extracellular and lysosomal thyroglobulin proteolysis, both essential steps for thyroid hormone synthesis

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“…All animal procedures were carried out in accordance with the National Institute of Health Guide for the Care and Use of Laboratory Animals and approved by the Animal Care and Use Committee of Kyoto Pharmaceutical University. Primary neuronal cultures were prepared from the cerebral cortex of fetal mice, as described previously (15,16). Briefly, 15-day-old-fetal mouse was decapitated under ether anesthesia, and their brains were quickly removed.…”

Section: Cell Culturementioning

confidence: 99%

Functional Expression of Taurine Transporter and its Up-Regulation in Developing Neurons from Mouse Cerebral Cortex

et al. 2006

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Functional linkage of H+/peptide transporter PEPT2 and Na+/H+ exchanger in primary cultures of astrocytes from mouse cerebral cortex

Cited by 32 publications

References 42 publications

The Peptide Transporter PEPT2 is Targeted by the Protein Kinase SGK1 and the Scaffold Protein NHERF2

The Peptide Transporter PEPT2 is Targeted by the Protein Kinase SGK1 and the Scaffold Protein NHERF2

Functional expression of SLC15 peptide transporters in rat thyroid follicular cells

Functional Expression of Taurine Transporter and its Up-Regulation in Developing Neurons from Mouse Cerebral Cortex

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