The in vitro formation of recombinant tau polymers: effect of phosphorylation and glycation.

Tau Isolated from paired helical filaments, aberrant structures that appear in Alzheimer disease (AD) patients' brains, show at least two posttranslational modifications: phosphorylation (Grundke-Iqbal et al., 1986; Ihara et al., 1986) and glycation (Ledesma et al., 1994; Yan et al., 1994). To test whether these modifications could affect the capacity of tau to self-aggregate, recombinant tau was phosphorylated and glycated, and its capacity to form polymers analyzed. Our results indicate that on phosphorylation and glycation, the capacity of tau to form aggregates increases, and that glycation of tau could stabilize the assembled polymers and could facilitate formation of bundles from these polymers.