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Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters

ABSTRACT: The high‐affinity/low‐capacity system Slc15a2 (PepT2) is responsible for the reuptake of di/tripeptides from the renal proximal tubule, but it also operates in many other tissues and organs. Information regarding PepT2 in teleost fish is limited and, to date, functional data are available...

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Autores principales: Vacca, Francesca, Gomes, Ana S., Murashita, Koji, Cinquetti, Raffella, Roseti, Cristina, Barca, Amilcare, Rønnestad, Ivar, Verri, Tiziano, Bossi, Elena
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9321897/
https://www.ncbi.nlm.nih.gov/pubmed/35413133
http://dx.doi.org/10.1113/JP282781
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author Vacca, Francesca
Gomes, Ana S.
Murashita, Koji
Cinquetti, Raffella
Roseti, Cristina
Barca, Amilcare
Rønnestad, Ivar
Verri, Tiziano
Bossi, Elena
author_facet Vacca, Francesca
Gomes, Ana S.
Murashita, Koji
Cinquetti, Raffella
Roseti, Cristina
Barca, Amilcare
Rønnestad, Ivar
Verri, Tiziano
Bossi, Elena
author_sort Vacca, Francesca
collection PubMed
description ABSTRACT: The high‐affinity/low‐capacity system Slc15a2 (PepT2) is responsible for the reuptake of di/tripeptides from the renal proximal tubule, but it also operates in many other tissues and organs. Information regarding PepT2 in teleost fish is limited and, to date, functional data are available from the zebrafish (Danio rerio) only. Here, we report the identification of two slc15a2 genes in the Atlantic salmon (Salmo salar) genome, namely slc15a2a and slc15a2b. The two encoded PepT2 proteins share 87% identity and resemble both structurally and functionally the canonical vertebrate PepT2 system. The mRNA tissue distribution analyses reveal a widespread distribution of slc15a2a transcripts, being more abundant in the brain and gills, while slc15a2b transcripts are mainly expressed in the kidney and the distal part of the gastrointestinal tract. The function of the two transporters was investigated by heterologous expression in Xenopus laevis oocytes and two‐electrode voltage‐clamp recordings of transport and presteady‐state currents. Both PepT2a and PepT2b in the presence of Gly‐Gln elicit pH‐dependent and Na(+) independent inward currents. The biophysical and kinetic analysis of the recorded currents defined the transport properties, confirming that the two Atlantic salmon PepT2 proteins behave as high‐affinity/low‐capacity transporters. The recent structures and the previous kinetic schemes of rat and human PepT2 qualitatively account for the characteristics of the two Atlantic salmon proteins. This study is the first to report on the functional expression of two PepT2‐type transporters that operate in the same vertebrate organism as a result of (a) gene duplication process(es). KEY POINTS: Two slc15a2‐type genes, slc15a2a and slc15a2b coding for PepT2‐type peptide transporters were found in the Atlantic salmon. slc15a2a transcripts, widely distributed in the fish tissues, are abundant in the brain and gills, while slc15a2b transcripts are mainly expressed in the kidney and distal gastrointestinal tract. Amino acids involved in vertebrate Slc15 transport function are conserved in PepT2a and PepT2b proteins. Detailed kinetic analysis indicates that both PepT2a and PepT2b operate as high‐affinity transporters. The kinetic schemes and structures proposed for the mammalian models of PepT2 are suitable to explain the function of the two Atlantic salmon transporters.
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spelling pubmed-93218972022-07-30 Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters Vacca, Francesca Gomes, Ana S. Murashita, Koji Cinquetti, Raffella Roseti, Cristina Barca, Amilcare Rønnestad, Ivar Verri, Tiziano Bossi, Elena J Physiol Molecular and Cellular ABSTRACT: The high‐affinity/low‐capacity system Slc15a2 (PepT2) is responsible for the reuptake of di/tripeptides from the renal proximal tubule, but it also operates in many other tissues and organs. Information regarding PepT2 in teleost fish is limited and, to date, functional data are available from the zebrafish (Danio rerio) only. Here, we report the identification of two slc15a2 genes in the Atlantic salmon (Salmo salar) genome, namely slc15a2a and slc15a2b. The two encoded PepT2 proteins share 87% identity and resemble both structurally and functionally the canonical vertebrate PepT2 system. The mRNA tissue distribution analyses reveal a widespread distribution of slc15a2a transcripts, being more abundant in the brain and gills, while slc15a2b transcripts are mainly expressed in the kidney and the distal part of the gastrointestinal tract. The function of the two transporters was investigated by heterologous expression in Xenopus laevis oocytes and two‐electrode voltage‐clamp recordings of transport and presteady‐state currents. Both PepT2a and PepT2b in the presence of Gly‐Gln elicit pH‐dependent and Na(+) independent inward currents. The biophysical and kinetic analysis of the recorded currents defined the transport properties, confirming that the two Atlantic salmon PepT2 proteins behave as high‐affinity/low‐capacity transporters. The recent structures and the previous kinetic schemes of rat and human PepT2 qualitatively account for the characteristics of the two Atlantic salmon proteins. This study is the first to report on the functional expression of two PepT2‐type transporters that operate in the same vertebrate organism as a result of (a) gene duplication process(es). KEY POINTS: Two slc15a2‐type genes, slc15a2a and slc15a2b coding for PepT2‐type peptide transporters were found in the Atlantic salmon. slc15a2a transcripts, widely distributed in the fish tissues, are abundant in the brain and gills, while slc15a2b transcripts are mainly expressed in the kidney and distal gastrointestinal tract. Amino acids involved in vertebrate Slc15 transport function are conserved in PepT2a and PepT2b proteins. Detailed kinetic analysis indicates that both PepT2a and PepT2b operate as high‐affinity transporters. The kinetic schemes and structures proposed for the mammalian models of PepT2 are suitable to explain the function of the two Atlantic salmon transporters. John Wiley and Sons Inc. 2022-04-28 2022-05-15 /pmc/articles/PMC9321897/ /pubmed/35413133 http://dx.doi.org/10.1113/JP282781 Text en © 2022 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ (https://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
spellingShingle Molecular and Cellular
Vacca, Francesca
Gomes, Ana S.
Murashita, Koji
Cinquetti, Raffella
Roseti, Cristina
Barca, Amilcare
Rønnestad, Ivar
Verri, Tiziano
Bossi, Elena
Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
title Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
title_full Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
title_fullStr Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
title_full_unstemmed Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
title_short Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
title_sort functional characterization of atlantic salmon (salmo salar l.) pept2 transporters
topic Molecular and Cellular
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9321897/
https://www.ncbi.nlm.nih.gov/pubmed/35413133
http://dx.doi.org/10.1113/JP282781
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