Journal of Proteomics & Bioinformatics
Open Access

Elucidating the functional roles of tissue specific Na, K-ATPase subunit combinations in the large milkweed bug Oncopeltus fasciatus

Joint Event on 12^th International Conference and Expo on Proteomics and Molecular Medicine & 12^th International Conference on Advancements in Bioinformatics and Drug Discovery

November 26-28, 2018 | Dublin, Ireland

Marlena Winter, Safaa Dalla, Jennifer Lohr and Susanne Dobler

Universitat Hamburg, Germany
University College London, UK

Posters & Accepted Abstracts: J Proteomics Bioinform

Abstract :

The well-studied transmembrane enzyme Na, K-ATPase is essential for the maintenance of membrane potentials and functionality of cells. Plant toxins like cardenolides inhibit the enzyme resulting in harmful or even lethal effects. Oncopeltus fasciatus is one of few insect species that is insensitive to these toxins. This insensitivity is gained by amino acid substitutions in the cardenolide binding pocket of the catalytic Na, K-ATPase alpha-subunit. Furthermore, two rounds of gene duplications of the α-subunit gave rise to three paralogs (A, B, C) that differ in number and identity of these substitutions. Additionally, four copies of the β-subunit exist, which form heterodimers with the α-subunit paralogs and are expected to modulate the Na, K-ATPases behavior. We found that nine different α/β-subunit combinations expressed in cell culture show different insensitivities against the two cardenolides ouabain and calotropin, differing in polarity, structure, steric conformation and inhibitory potential. But so far, nothing is known about the tissue specific α/β-subunit combinations and their functional roles. The already detected expression patterns hint to different functions that trade-off ion transport, cardenolide insensitivity and morphogenetic potential of the β-subunit in a tissue specific manner. Therefore, we suggest that the evolution of three α-subunit paralogs combined with one of the four β-subunits enables O. fasciatus to adjust the Na, K-ATPases performance to fulfill particular tissue specific functional roles. We are currently elucidating the protein abundances of the α/β-subunit combinations in nerves, ovaries, muscles, hindgut and Malpighian tubules followed by targeted gene-knockdowns to analyze the functional roles and differences between the Na, K-ATPase α/β-subunit combinations.

Biography :

E-mail: marlena.winter@studium.uni-hamburg.de