Modulation By K+ Plus NH4+ of Microsomal (Na+, K+)ATPase Activity in Selected Ontogenetic Stages of the Diadromous River Shrimp Macrobrachium amazonicum (Decapoda, Palaemonidae)

Autor(es)

Leone, Francisco A. ^[1] ; Bezerra, Thais M. S. ^[1] ; Garcon, Daniela P. ^[2] ; Lucena, Malson N. ^[3] ; Pinto, Marcelo R. ^[1] ; Fontes, Carlos F. L. ^[4] ; McNamara, John C. ^[5]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Ribeirao Preto, SP - Brazil

^[2] Univ Fed Paraiba, Ctr Ciencias Exatas & Natureza, Dept Biol Mol, BR-58059900 Joao Pessoa, Paraiba - Brazil

^[3] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Bioquim & Imunol, BR-14049 Ribeirao Preto, SP - Brazil

^[4] Univ Fed Rio de Janeiro, Inst Bioquim Med, Rio De Janeiro, RJ - Brazil

^[5] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 9, n. 2 FEB 21 2014.
• Citações Web of Science: 12

Resumo

We investigate the synergistic stimulation by K+ plus NH4+ of (Na+, K+)-ATPase activity in microsomal preparations of whole zoea I and decapodid III, and in juvenile and adult river shrimp gills. Modulation of (Na+, K+)-ATPase activity is ontogenetic stage-specific, and particularly distinct between juveniles and adults. Although both gill enzymes exhibit two different sites for K+ and NH4+ binding, in the juvenile enzyme, these two sites are equivalent: binding by both ions results in slightly stimulated activity compared to that of a single ionic species. In the adult enzyme, the sites are not equivalent: when one ion occupies its specific binding site, (Na+, K+)-ATPase activity is stimulated synergistically by approximate to 50% on binding of the complementary ion. Immunolocalization reveals the enzyme to be distributed predominantly throughout the intralamellar septum in the gill lamellae of juveniles and adults. Western blot analyses demonstrate a single immunoreactive band, suggesting a single (Na+, K+)-ATPase alpha-subunit isoform that is distributed into different density membrane fractions, independently of ontogenetic stage. We propose a model for the modulation by K+ and NH4+ of gill (Na+, K+)-ATPase activity. These findings suggest that the gill enzyme may be regulated by NH4+ during ontogenetic development in M. amazonicum. (AU)

• Processo FAPESP: 10/17534-0 - Papel da (Na,K)-ATPase na osmorregulação e excreção de amônio em crustáceos eurialinos: identificação e efeitos do FXYD2 na regulação da (Na,K)-ATPase branquial do siri Callinectes danae
• Beneficiário: Francisco de Assis Leone
• Modalidade de apoio: Auxílio à Pesquisa - Regular