Dataset Information

Na+/K+-ATPase ?-subunit (nka?) isoforms and their mRNA expression levels, overall Nka? protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus.

ABSTRACT: This study aimed to obtain the coding cDNA sequences of Na+/K+-ATPase ? (nka?) isoforms from, and to quantify their mRNA expression in, the skeletal muscle (SM), the main electric organ (EO), the Hunter's EO and the Sach's EO of the electric eel, Electrophorus electricus. Four nka? isoforms (nka?1c1, nka?1c2, nka?2 and nka?3) were obtained from the SM and the EOs of E. electricus. Based on mRNA expression levels, the major nka? expressed in the SM and the three EOs of juvenile and adult E. electricus were nka?1c1 and nka?2, respectively. Molecular characterization of the deduced Nka?1c1 and Nka?2 sequences indicates that they probably have different affinities to Na+ and K+. Western blotting demonstrated that the protein abundance of Nka? was barely detectable in the SM, but strongly detected in the main and Hunter's EOs and weakly in the Sach's EO of juvenile and adult E. electricus. These results corroborate the fact that the main EO and Hunter's EO have high densities of Na+ channels and produce high voltage discharges while the Sach's EO produces low voltage discharges. More importantly, there were significant differences in kinetic properties of Nka among the three EOs of juvenile E. electricus. The highest and lowest Vmax of Nka were detected in the main EO and the Sach's EO, respectively, with the Hunter's EO having a Vmax value intermediate between the two, indicating that the metabolic costs of EO discharge could be the highest in the main EO. Furthermore, the Nka from the main EO had the lowest Km (or highest affinity) for Na+ and K+ among the three EOs, suggesting that the Nka of the main EO was more effective than those of the other two EOs in maintaining intracellular Na+ and K+ homeostasis and in clearing extracellular K+ after EO discharge.

SUBMITTER: Ching B

PROVIDER: S-EPMC4368207 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Na+/K+-ATPase α-subunit (nkaα) isoforms and their mRNA expression levels, overall Nkaα protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus.

Ching Biyun B Woo Jia M JM Hiong Kum C KC Boo Mel V MV Choo Celine Y L CY Wong Wai P WP Chew Shit F SF Ip Yuen K YK

PloS one 20150320 3

This study aimed to obtain the coding cDNA sequences of Na+/K+-ATPase α (nkaα) isoforms from, and to quantify their mRNA expression in, the skeletal muscle (SM), the main electric organ (EO), the Hunter's EO and the Sach's EO of the electric eel, Electrophorus electricus. Four nkaα isoforms (nkaα1c1, nkaα1c2, nkaα2 and nkaα3) were obtained from the SM and the EOs of E. electricus. Based on mRNA expression levels, the major nkaα expressed in the SM and the three EOs of juvenile and adult E. elect ...[more]

PMID: 25793901

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Project description:Fishes are equipped to sense stressful stimuli and are able to respond to environmental stressor such as hypoxia with varying pattern of stress response. The functional attributes of brain to hypoxia stress in relation to ion transport and its interaction during immune challenge have not yet delineated in fish. We, therefore, explored the pattern of ion transporter functions and messenger RNA (mRNA) expression of ?1-subunit isoforms of Na+/K+-ATPase (NKA) in the brain segments, namely, prosencephalon (PC), mesencephalon (MC), and metencephalon (MeC) in an obligate air-breathing fish exposed either to hypoxia stress (30 minutes forced immersion in water) or challenged with zymosan treatment (25-200 ng g-1 for 24 hours) or both. Zymosan that produced nonspecific immune responses evoked differential regulation of NKA, H+/K+-ATPase (HKA), and [Formula: see text] (NNA) in the varied brain segments. On the contrary, hypoxia stress that demanded activation of NKA in PC and MeC showed a reversed NKA activity pattern in MeC of immune-challenged fish. A compromised HKA and NNA regulation during hypoxia stress was found in immune-challenged fish, indicating the role of these brain ion transporters to hypoxia stress and immune challenges. The differential mRNA expression of ?1-subunit isoforms of NKA, nka?1a, nka?1b, and nka?1c, in hypoxia-stressed brain showed a shift in its expression pattern during hypoxia stress-immune interaction in PC and MC. Evidence is thus presented for the first time that ion transporters such as HKA and NNA along with NKA act as functional brain markers which respond differentially to both hypoxia stress and immune challenges. Taken together, the data further provide evidence for a differential Na+, K+, H+, and [Formula: see text] ion signaling that exists in brain neuronal clusters during hypoxia stress-immune interaction as a result of modified regulations of NKA, HKA, and NNA transporter functions and nka?1 isoform regulation.

Dataset Information

Na+/K+-ATPase ?-subunit (nka?) isoforms and their mRNA expression levels, overall Nka? protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus.

Publications

Na+/K+-ATPase α-subunit (nkaα) isoforms and their mRNA expression levels, overall Nkaα protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus.

Similar Datasets

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