MAPT and Alzheimer disease: In conclusion, MB binds to PMCA at micromolar concentrations and can reverse the inhibition produced by tau in the ATPase activity of PMCA of human brain membranes prepared from AD and age-matched control samples, purified pig brain PMCA, or purified yeast hPMCA4b reconstituted in PS or PC, and membranes of COS cells overexpressing hPMCA2b or hPMCA4b.