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| Format: | Artículo científico |
| Sprache: | en |
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Zoological science
2026
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| Online-Zugang: | https://pubmed.ncbi.nlm.nih.gov/42080275/ |
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Inhaltsangabe:
- Differential Expression of Na/K-ATPase α -Subunit Isoforms in Functionally Distinct Types of Ionocytes in the Gills of Mozambique Tilapia. Miyanishi, Hiroshi Maeda, Shotaro Ohtani-Kaneko, Ritsuko Kaneko, Toyoji Animals Sodium-Potassium-Exchanging ATPase Gills Tilapia Gene Expression Regulation, Enzymologic Isoenzymes Protein Isoforms Phylogeny Protein Subunits Na/K-ATPase (Nka) is essential for maintaining body fluid homeostasis in teleost osmoregulatory epithelia. In the present study, we identified six Nka α-subunit isoforms, including those previously reported in Mozambique tilapia. Among the Nka α-subunit isoforms, , , , and were highly expressed in the gills. In the gills of freshwater (FW)-acclimated fish, the expression levels of , were the highest, and those of and were moderately expressed, whereas in the gills of seawater (SW)-acclimated fish, expression was the highest, followed by . We also investigated the expressions of the four Nka α-subunit isoforms in the four types of ionocytes by means of triple fluorescence staining with whole-mount in situ hybridization and immunocytochemistry. The Nka α-subunit isoforms showed differential expression in functionally distinct types of ionocytes in Mozambique tilapia. Only was expressed in type I ionocytes, which are considered to be in the immature or resting phase. is the major isoform in type II ionocytes that absorb Na and Cl through apically-located Na/Cl cotransporter 2 (Ncc2) in FW. Type III ionocytes, which absorb Na in exchange for H through apical Na/H exchanger 3 (Nhe3) in FW, mainly expressed , with moderate expression of and . Type IV ionocytes that secrete Na and Cl- in SW expressed mainly and, secondarily . It should be noted that is the major Nka α-subunit isoform in both type III and type IV ionocytes, which are substantially the same cell type with functional plasticity.