ESPELT Maria Victoria
Epigallocatechin 3-gallate inhibits the plasma membrane Ca2+-ATPase: effects on calcium homeostasis
RINALDI, DÉBORA E.; ONTIVEROS, MALLKU Q.; SAFFIOTI, NICOLAS A.; VIGIL, MAXIMILIANO A.; MANGIALAVORI, IRENE C.; ROSSI, ROLANDO C.; ROSSI, JUAN P.; ESPELT, MARÍA V.; FERREIRA-GOMES, MARIELA S.
Año: 2021 vol. 7
Flavonoids are natural compounds responsible for the health benefits of green tea. Some of the flavonoids present ingreen tea are catechins, among which are:epigallocatechin, epicatechin-3-gallate, epicatechin, catechin and epigallocatechin-3-gallate (EGCG).The latter was found to induce apoptosis, reduce reactive oxygen species, induce cell cycle arrest and inhibit carcinogenesis. EGCG also was found to be involved in calcium (Ca2+) homeostasis in excitable and in non-excitable cells.In this study, we investigate the effect of catechins on plasma membrane Ca2+-ATPase (PMCA), which is one of the main mechanisms that extrude Ca2+ out of the cell. Our studies comprised experiments on the isolated PMCA and on cells overexpressing the pump. Among catechins that inhibited PMCA activity, the mostpotent inhibitor was EGCG. EGCG inhibited PMCA activity in a reversible way favoringE1P conformation. EGCG inhibition also occurredin the presence of calmodulin, the main pump activator. Finally, the effect of EGCG on PMCA activity was studied in human embryonic kidney cells (HEK293T) that transiently overexpress hPMCA4. Results show that EGCG inhibited PMCA activity in HEK293T cells, suggesting that the effects observed on isolated PMCA occur in living cells.