PubMed:29047027 JSONTXT

{"project":"silkworm","denotations":[{"id":"T1","span":{"begin":41,"end":49},"obj":"Species:7091"},{"id":"T2","span":{"begin":94,"end":102},"obj":"Species:7091"},{"id":"T3","span":{"begin":154,"end":163},"obj":"Species:9606"},{"id":"T4","span":{"begin":298,"end":306},"obj":"Species:7091"},{"id":"T5","span":{"begin":308,"end":319},"obj":"Species:7091"},{"id":"T6","span":{"begin":637,"end":640},"obj":"Species:9823"},{"id":"T7","span":{"begin":732,"end":741},"obj":"Species:9606"},{"id":"T8","span":{"begin":825,"end":833},"obj":"Species:7091"},{"id":"T9","span":{"begin":1030,"end":1038},"obj":"Species:7091"}],"text":"A possible mechanism for low affinity of silkworm Na+/K+-ATPase for K.\nThe affinity for K+ of silkworm nerve Na+/K+-ATPase is markedly lower than that of mammalian Na+/K+-ATPase (Homareda 2010). In order to obtain clues on the molecular basis of the difference in K+ affinities, we cloned cDNAs of silkworm (Bombyx mori) nerve Na+/K+-ATPase α and β subunits, and analyzed the deduced amino acid sequences. The molecular masses of the α and β subunits were presumed to be 111.5 kDa with ten transmembrane segments and 37.7 kDa with a single transmembrane segment, respectively. The α subunit showed 75% identity and 93% homology with the pig Na+/K+-ATPase α1 subunit. On the other hand, the amino acid identity of the β subunit with mammalian counterparts was as low as 30%. Cloned α and β cDNAs were co-expressed in cultured silkworm ovary-derived cells, BM-N cells, which lack endogenous Na+/K+-ATPase. Na+/K+-ATPase expressed in the cultured cells showed a low affinity for K+ and a high affinity for Na+, characteristic of the silkworm nerve Na+/K+-ATPase. These results suggest that the β subunit is responsible for the affinity for K+ of Na+/K+-ATPase."}

{"project":"silkwormbase","denotations":[{"id":"T1","span":{"begin":41,"end":49},"obj":"Species:7091"},{"id":"T2","span":{"begin":94,"end":102},"obj":"Species:7091"},{"id":"T3","span":{"begin":154,"end":163},"obj":"Species:9606"},{"id":"T4","span":{"begin":298,"end":306},"obj":"Species:7091"},{"id":"T5","span":{"begin":308,"end":319},"obj":"Species:7091"},{"id":"T6","span":{"begin":637,"end":640},"obj":"Species:9823"},{"id":"T7","span":{"begin":732,"end":741},"obj":"Species:9606"},{"id":"T8","span":{"begin":825,"end":833},"obj":"Species:7091"},{"id":"T9","span":{"begin":1030,"end":1038},"obj":"Species:7091"}],"text":"A possible mechanism for low affinity of silkworm Na+/K+-ATPase for K.\nThe affinity for K+ of silkworm nerve Na+/K+-ATPase is markedly lower than that of mammalian Na+/K+-ATPase (Homareda 2010). In order to obtain clues on the molecular basis of the difference in K+ affinities, we cloned cDNAs of silkworm (Bombyx mori) nerve Na+/K+-ATPase α and β subunits, and analyzed the deduced amino acid sequences. The molecular masses of the α and β subunits were presumed to be 111.5 kDa with ten transmembrane segments and 37.7 kDa with a single transmembrane segment, respectively. The α subunit showed 75% identity and 93% homology with the pig Na+/K+-ATPase α1 subunit. On the other hand, the amino acid identity of the β subunit with mammalian counterparts was as low as 30%. Cloned α and β cDNAs were co-expressed in cultured silkworm ovary-derived cells, BM-N cells, which lack endogenous Na+/K+-ATPase. Na+/K+-ATPase expressed in the cultured cells showed a low affinity for K+ and a high affinity for Na+, characteristic of the silkworm nerve Na+/K+-ATPase. These results suggest that the β subunit is responsible for the affinity for K+ of Na+/K+-ATPase."}