PUBLICATION
Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters
- Authors
- Vacca, F., Gomes, A.S., Murashita, K., Cinquetti, R., Roseti, C., Barca, A., Rønnestad, I., Verri, T., Bossi, E.
- ID
- ZDB-PUB-220413-25
- Date
- 2022
- Source
- The Journal of physiology 600(10): 2377-2400 (Journal)
- Registered Authors
- Keywords
- Di/tripeptide transport(ers), PepT2a, PepT2b, Slc15a2a, Slc15a2b, Xenopus laevis oocytes, presteady state currents, two-electrode voltage-clamp, whole genome duplication
- MeSH Terms
-
- Animals
- Kinetics
- Mammals/metabolism
- Oocytes/metabolism
- Rats
- Salmo salar*/genetics
- Salmo salar*/metabolism
- Symporters*/genetics
- Symporters*/metabolism
- Zebrafish/genetics
- PubMed
- 35413133 Full text @ J. Physiol.
Citation
Vacca, F., Gomes, A.S., Murashita, K., Cinquetti, R., Roseti, C., Barca, A., Rønnestad, I., Verri, T., Bossi, E. (2022) Functional characterization of Atlantic salmon (Salmo salar L.) PepT2 transporters. The Journal of physiology. 600(10):2377-2400.
Abstract
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 brain and gills, while slc15a2b transcripts are mainly expressed in 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.
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/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 to 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 kidney and distal part of 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). Abstract figure legend This article is protected by copyright. All rights reserved.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping