INVESTIGADORES
MONESTEROLO Noelia Edith
artículos
Título:
Activation of PMCA by calmodulin or ethanol in plasma membrane vesicles from rat brain involves dissociation of the acetylated tubulin/PMCA complex
Autor/es:
NOELIA E. MONESTEROLO; VERONICA S. SANTANDER; ALEXIS N. CAMPETELLI; CARLOS A. ARCE; HECTOR S. BARRA; CESAR H. CASALE
Revista:
FEBS Journal
Editorial:
Blackwell Publishing
Referencias:
Lugar: Cambridge; Año: 2008 vol. 275 p. 3567 - 3579
ISSN:
1432-1033
Resumen:
We have recently shown that acetylated tubulin interacts with plasma membrane
Na+,K+-ATPase and inhibits its enzyme activity in several types of
cells. H+-ATPase of Saccharomyces cerevisiae is similarly inhibited by
interaction with acetylated tubulin. The activities of both these ATPases
are restored upon dissociation of the acetylated tubulin -ATPase complex.
Here, we report that in plasma membrane vesicles isolated from brain synaptosomes,
another P-type ATPase, plasma membrane Ca2+-ATPase
(PMCA), undergoes enzyme activity regulation by its association -dissociation
with acetylated tubulin. The presence of acetylated tubulin -PMCA
complex in membrane vesicles was demonstrated by analyzing the behavior
of acetylated tubulin in a detergent partition, and by immunoprecipitation
experiments. PMCA is known to be stimulated by ethanol and calmodulin
at physiological concentrations. We found that treatment of plasma membrane
vesicles with these reagents induced dissociation of the complex, with
a concomitant restoration of enzyme activity. Conversely, incubation of
vesicles with exogenous tubulin induced the association of acetylated tubulin
with PMCA, and the inhibition of enzyme activity. These findings indicate
that activation of synaptosomal PMCA by ethanol and calmodulin
involves dissociation of the acetylated tubulin-PMCA complex. This regulatory
mechanism was shown to also operate in living cells.