... hyperphosphorylated form [5–8]assembles into fibrillar polymers. The mechanism for that aberrant tau assembly has been widely analyzed by severalgroups, i ndicating that sulfated glycosaminoglycans ... cells is in hyperphosphorylated formTreatment of SH-SY 5Y human neuroblastoma cells withokadaic acid (OA), a phosphatase inh ibitor, results in thehyperphosphorylation of tau protein, as determined ... howed, in a cell-free system [17] thatphosphorylated tau, in the presence of H NE, polymerizesinto fibrillar polymers. To test if, i n a similar way, tau couldform aggregates in cultured cells, ...