Inhibition of the Plasma membrane Ca2+-ATPase by Epigallocatechin 3-gallate

RINALDI, D.E.; FERREIRA-GOMES, M.; MANGIALAVORI, I.C; AMABLE, G.; REY, O.; ROSSI J.P.

Mar del Plata

Congreso; 240. LI Reunión Anual de la Sociedad Argentina de Investigaciones Bioquímicas; 2015

Sociedad Argentina de Investigaciones Bioquímicas

Inhibition of the Plasmamembrane Ca2+-ATPase by Epigallocatechin-3-gallate Rinaldi, D.E.1; Ferreira-Gomes, M.1; Mangialavori, I.1; Amable,G.2; Rey, O.2; Rossi, J.P.1 1IQUFIB. Dto de QuímicaBiológica. FFyB, UBA. 2INIGEM.Cátedra de Genética. FFyB, UBA.  Green  tea polyphenols  are  natural plant  flavonoids  and comprise  many  types of  catechins. Epigallocatechingallate   (EGCg)   is  the   major   polyphenol  component and   primarilyresponsible for the green tea effects. EGCgbeneficial effects include mainly antioxidant,anti-inflammatory and neuroprotective effects.Previous studies showed that EGCg inhibits the Na+,K+-ATPaseactivity by reducing the rate of the E1P to E2Ptransition through interaction with plasma membrane phospholipids.The purpose of this work is to investigate theeffect of EGCgon thePlasma membrane Ca2+- ATPase (PMCA)as anothermember of the P-type ATPases family.We examined the effects ofEGCg on the PMCA activityby using vesicles from human red blood cells. The EGCgshowed an inhibitory effect on the Ca2+ ATPase activity in adose-dependent manner with K0.5values of 3.5 mM. This valuewas similar to those found for Na+, K+-ATPase.One biological actionattributed to EGCg is the ability to influence intracellular Ca2+ inboth non-excitable and excitable cells. We characterized EGCg-regulated Ca2+signaling bycytoplasmic free Ca2+measurements using Fluo4-AM. EGCgdecreasedthe rate of removal of Ca2+in HEK293 cellswith respect to the control,suggesting that those systems that removecalciumincluding PMCA would be affected, through a process thatremains to be determined.