Since ventricular fibrillation completely prevents the heart from functioning as a pump, it quickly brings death unless emergency measures restore the circulation of oxygenated blood throughout the body.
For example, we can use a fan to pump some noxious gas from one room to another, or to the outside of a building; but if we set a fan on the lawn, it may beat the air, but is not (functioning as) a pump.
"It opened a whole new era for understanding how the heart functions as a pump and what goes wrong when it fails to pump efficiently," said Dr. Heinrich Taegtmeyer, a professor of medicine at the University of Texas Health Science Center in Houston.
We have recently demonstrated that overexpressed MRP4 plays a major role in reducing the accumulation of [C] 6-mercaptopurine (6-MP) and/or its metabolites by functioning as an efflux pump, thereby conferring resistance to 6-MP in acute lymphoblastic leukemia (ALL) [28].
As the biological action of Ssd resembled thapsigargin, a potent inhibitor of the SERCA pump, which induces autophagy through perturbing calcium homeostasis, we postulated that Ssd might also function as a SERCA pump inhibitor.
The protein functions as a proton pump, moving protons through the cell membrane to alter the cell's voltage.
A decade has passed since Beja et al. first identified [1] and characterized [2] proteorhodopsin (PR) genes from uncultivated bacterioplankton, showing that PR functioned as a proton pump when cloned and expressed in E. coli.
Despite the publication of redox-dependent sodium translocation by mitochondrial enzyme [16], no indications suggesting that complex I functioned as a sodium pump were found [15,30].
(ii) In the absence of NaCl (which was replaced by KCl), light-induced acidification was observed, which was eliminated in turn by CCCP, indicating that in the absence of Na+ the protein can function as a proton pump.
We demonstrate that cross-resistance between aminopyrazole and spiroindolone series is mediated by mutations in pfatp4, a gene encoding a P-type ATPase that functions as a Na+/H+ pump at the parasite plasma membrane.
ATPase activity and the formation of phosphointermediates verify the full function of the enzyme: the ATPase is inhibited by vanadate (IC50= 119 μM) and the formation of phosphorylated enzyme intermediates shown by acidic PAGE depends on calcium, indicating that the Synechocystis P-ATPase functions as a calcium pump.
