A kinetic characterization of the gill V(H+)-ATPase in juvenile and adult Macrobrachium amazonicum, a diadromous palaemonid shrimp

Author(s)

Lucena, Malson N. ^[1] ; Pinto, Marcelo R. ^[1] ; Garcon, Daniela P. ^[2] ; McNamara, John C. ^[3] ; Leone, Francisco A. ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras, Dept Quim, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras, Dept Biol, BR-14040901 Ribeirao Preto, SP - Brazil

^[3] Univ Fed Paraiba, Ctr Ciencias Exatas & Nat, Dept Biol Mol, BR-58059900 Joao Pessoa, Paraiba - Brazil

• Document type: Journal article
• Source: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY; v. 181, p. 15-25, MAR 2015.
• Web of Science Citations: 10

Abstract

Novel kinetic properties of a microsomal gill V(H+)-ATPase from juvenile and adult Amazon River shrimp, Macrobrachium amazonicum, are described. While protein expression patterns are markedly different, Western blot analysis reveals a sole immunoreactive band, suggesting a single V(H+)-ATPase subunit isoform, distributed in membrane fractions of similar density in both ontogenetic stages. Immunofluorescence labeling locates the V(H+)-ATPase in the apical regions of the lamellar pillar cells in both stages in which mRNA expression of the V(H+)-ATPase B-subunit is identical. Juvenile (36.6 +/- 33 nmol Pi min(-1) mg(-1)) and adult (41.6 +/- 13 nmol P-i min(-1) mg(-1)) V(H+)-ATPase activities are similar, the apparent affinity for ATP of the adult enzyme (K-0.5 = 0.21 +/- 0.02 mmol L-1) being 3-fold greater than for juveniles (K-0.5 = 0.61 +/- 0.01 mmol L-1). The K-0.5 for Mg2+ interaction with the juvenile V(H+)-ATPase (1.40 +/- 0.07 mmol L-1) is 6-fold greater than for adults (026 +/- 0.02 mmol L-1) while the bafilomycin A1 inhibition constant (K-I) is 45.0 +/- 2.3 nmol L-1 and 24.2 +/- 12 nmol L-1, for juveniles and adults, respectively. Both stages exhibited residual bafilomycin-insensitive ATPase activity of approximate to 25 nmol P-i, min(-1) mg(-1), suggesting the presence of ATPases other than the V(H+)-ATPase. These differences may reflect a long-term regulatory mechanism of V(H+)-ATPase activity, and suggest stage-specific enzyme modulation. This is the first kinetic analysis of V(H+)-ATPase activity in different ontogenetic stages of a freshwater shrimp and allows better comprehension of the biochemical adaptations underpinning the establishment of palaemonid shrimps in fresh water. (C) 2014 Elsevier Inc All rights reserved. (AU)

• FAPESP's process: 10/17534-0 - Role of (Na,K)-ATPase in osmoregulation and excretion of ammonium ions in euryhaline crustaceans: identification and influence of FXYD2 on the regulation of gill (Na,K)-ATPase of the crab Callinectes danae
• Grantee: Francisco de Assis Leone
• Support Opportunities: Regular Research Grants
• FAPESP's process: 10/06395-9 - Role of (Na,K)-ATPase in osmorregulation and excretion of ammonium ions in euryhaline crustaceans: identification and influence of FXYD2 on the regulation of gill (Na,K)-ATPase of the crab Callinectes danae
• Grantee: Daniela Pereira Garçon
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 10/16115-3 - Ontogeny of osmoregulation in the freshwater Shrimp Macrobrachium amazonicum (Heller, 1862): the expression of (na +, K +)-ATPase, influence of lipid composition and role of polyamines in the kinetic activity of the enzyme
• Grantee: Malson Neilson de Lucena
• Support Opportunities: Scholarships in Brazil - Doctorate