Brain plasma membrane Na+,K+-ATPase is inhibited by acetylated tubulin
C H Casale1, A D Alonso, H S Barra
1Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), UNC-CONICET, Departamento Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Cordoba, Argentina.
Abstract:
Membranes from brain tissue contain tubulin that can be isolated as a hydrophobic compound by partitioning into Triton X-114. The hydrophobic behavior of this tubulin is due to the formation of a complex with the alpha-subunit of Na+,K+-ATPase. In the present work we show that the interaction of tubulin with Na+K+-ATPase inhibits the enzyme activity. We found that the magnitude of the inhibition is correlated with: (1) concentration of the acetylated tubulin isoform present in the tubulin preparation used, and (2) amount of acetylated tubulin isoform isolated as a hydrophobic compound. In addition, some compounds involved in the catalytic action of Na+K+-ATPase were assayed to determine their effects on the inhibitory capability of tubulin on this enzyme. The inhibitory effect of tubulin was only slightly decreased by ATP at relatively low nucleotide concentration (0.06 mM). NaCl (1-160 mM) and KCl (0.2-10 mM) showed no effect whereas inorganic phosphate abolished the inhibitory effect of tubulin in a concentration-dependent manner.
Related Concept Videos
ATP Synthase: Mechanism
Destabilization of Microtubules
Drugs that Stabilize Microtubules
Microtubule Instability
ATP Driven Pumps III: V-type Pumps
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...


