MAPT and Alzheimer disease: Analysis of cell lysates from the AD brain by sodium dodecyl sulfate polyacrylamide gel electrophoresis reveals three major electrophoresis bands: tau proteins with relative molecular weights of 68,000, 64,000, and 60,000 (Lee et al., 1991; Goedert et al., 1992; Greenberg et al., 1992; Delacourte et al., 1999).