INVESTIGADORES
ROSSI juan pablo Francisco
congresos y reuniones científicas
Título:
Interaction between PMCA and unsaturated fatty acids: The use of a photoactivatable oleic acid analog
Autor/es:
MARIA FLORENCIA PIGNATARO, IRENE C. MANGIALAVORI, JOSE MARIA DELFINO, JUAN PABLO F.C. ROSSI.
Lugar:
Tucumán
Reunión:
Congreso; XLI Reunión Anual de la Sociedad Argentina de Biofísica (SAB).; 2012
Institución organizadora:
Sociedad Argentina de Biofísica
Resumen:
Interaction between PMCA and unsaturated fatty
acids: The use of a photoactivatable oleic acid analog Maria
Florencia Pignataro, Irene C. Mangialavori, Jose Maria Delfino, Juan
Pablo
F.C. Rossi. Libro de Resúmenes: Pag 226
The lipid environment
plays a central role in the regulation of integral membrane proteins biological
function. The modulation provided by the surrounding phospholipids, both
neutral or charged, has been extensively described whereas some knowledge
regarding regulation by unsaturated fatty acids (UFAs) still remains to be
gained. As an integral membranenprotein example to study this regulation, we
chose plasma membrane Ca2+-ATPase (PMCA) which is responsible for maintaining
the low calcium levels in resting cells. Niggli et al1 presented one of the
first evidences regarding the UFAs regulation over PMCA: Oleic acid increases
both Vmax and Ca2+ affinity. The purpose of this work was to further
characterize the mechanisms involved in the modulation exerted by UFAs on PMCA.
With this aim, we studied the interaction between purified PMCA of human red
blood cells and a photoactivatable oleic acid analog, 8-(5´-azido-O-hexanoylsalicylamido)
octanoic acid (AS86)2. Our results showed that AS86 interactsnon-covalently
with PMCA showing a biphasic behaviour, similar to that observed for the effect
of oleic acid1. Whenever AS86 interacts covalently with PMCA, it has no effect
on the ATPase activity in the presence of Ca2+ alone, however, when Calmodulin
(CaM) is present, increasing concentrations of this probe, generates an
inhibitory effect on PMCA activation by CaM.
In order to provide some insights in the elucidation of the region where UFAs
may interact with this enzyme, we performed several photolabeling experiments
with this probe, to consequently subject the sample to a mass spectrometer
analysis (MALDI-TOF), finding differential labeling in distinct domains of
PMCA.
1. Referencias: 1Niggli,V.,Adunyah, E.S., &
Carafoli, E. (1981) J. Biol. Chem. 256, 8588-8592
2. Rossi, J.P.,Delfino, J.M., Caride, A.J., &
Fernandez ,H.N. (1995) Biochemisty. 31, 11:3802-12
Con subsidios de ANPCyT, CONICET, UBA