title: Different expression patterns of renal Na+/K+-ATPase α-isoform-like proteins between tilapia and milkfish following salinity challenges.
abstract: Euryhaline teleosts can survive in a broad range of salinity via alteration of the molecular mechanisms in certain osmoregulatory organs, including in the gill and kidney. Among these mechanisms, Na+/K+-ATPase (NKA) plays a crucial role in triggering ion-transporting systems. The switch of NKA isoforms in euryhaline fish gills substantially contributes to salinity adaptation. However, there is little information about switches in the kidneys of euryhaline teleosts. Therefore, the responses of the renal NKA α-isoform protein switch to salinity challenge in euryhaline tilapia (Oreochromis mossambicus) and milkfish (Chanos chanos) with different salinity preferences were examined and compared in this study. Immunohistochemical staining in tilapia kidneys revealed the localization of NKA in renal tubules rather than in the glomeruli, similar to our previous findings in milkfish kidneys. Protein abundance in the renal NKA pan α-subunit-like, α1-, and α3-isoform-like proteins in seawater-acclimated tilapia was significantly higher than in the freshwater group, whereas the α2-isoform-like protein exhibited the opposite pattern of expression. In the milkfish, higher protein abundance in the renal NKA pan α-subunit-like and α1-isoform-like proteins was found in freshwater-acclimated fish, whereas no difference was found in the protein abundance of α2- and α3-isoform-like proteins between groups. These findings suggested that switches for renal NKA α-isoforms, especially the α1-isoform, were involved in renal osmoregulatory mechanisms of euryhaline teleosts. Moreover, differences in regulatory responses of the renal NKA α-subunit to salinity acclimation between tilapia and milkfish revealed that divergent mechanisms for maintaining osmotic balance might be employed by euryhaline teleosts with different salinity preferences.
authors: Department of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan.
authors: Wen-Kai
authors: WK
authors: Yang
authors: Graduate Institute of Science Education, National Changhua University of Education, Changhua 50007, Taiwan; Taichung Municipal Kuang Rong Junior High School, Taichung 41265, Taiwan.
authors: Chang-Hung
authors: CH
authors: Chung
authors: Department of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan.
authors: Hui Chen
authors: HC
authors: Cheng
authors: Department of Oceanography, National Sun Yat-sen University, Kaohsiung 80424, Taiwan. Electronic address: stressphysiologylab@gmail.com.
authors: Cheng-Hao
authors: CH
authors: Tang
authors: Department of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan; Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan. Electronic address: thlee@email.nchu.edu.tw.
authors: Tsung-Han
authors: TH
authors: Lee
mesh_terms: D000818:Animals; D015971:Gene Expression Regulation, Enzymologic; D007527:Isoenzymes / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D021381:Protein Transport; D054712:Salinity; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013045:Species Specificity; D017210:Tilapia / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Kidney; Milkfish; Na(+)/K(+)-ATPase; Salinity; Tilapia; α-isoform