Abstract
Antibody Ab262 was raised against a synthetic τ peptide (SKIGSTENLK, amino acids 258-267 of τ, termed Ser262 peptide). The antibody was more reactive with Ser262 peptide and unphosphorylated τ than a related phosphopeptide [SKIGS(P)TENLK, termed P-Ser262 peptide] and τ phosphorylated by a partially purified kinase, glycogen synthase kinase (GSK) 3β. Ab262 reacted poorly with a peptide having the sequence DRV-QSKIGSLD (amino acids 348-358). Treatment of P-Ser262 peptide or GSK 3β phosphorylated τ with alkaline phosphatase increased Ab262 immunoreactivity, indicating that Ab262 is a reagent useful for studying τ phosphorylation at the Ser262 residue. The Ab262 immunoreactivity was detected in τ from normal brains and Alzheimer paired helical filament (PHF-τ) and in PHFs. Alkaline phosphatase treatment had no effect on the Ab262 immunoreactivity of normal τ and PHF-τ but altered the Tau-1 and PHF-1 immunoreactivities. τ proteins from rat brains at 3 and 8 h postmortem exhibited 5 and 19%, respectively, more Ab262 immunoreactivity than τ from fresh tissues. In comparison, rat τ at 8 h postmortem was 40% more immunoreactive with Tau-1. The results suggest that Ser262 is not a major phosphorylation site in vivo. Moreover, there is little or no difference between PHF-τ and normal τ in the extent of phosphorylation at Ser262.
Original language | English (US) |
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Pages (from-to) | 1131-1139 |
Number of pages | 9 |
Journal | Journal of neurochemistry |
Volume | 66 |
Issue number | 3 |
DOIs | |
State | Published - Mar 1996 |
Keywords
- Alzheimer paired helical filament-τ
- Alzheimer's disease
- Peptide phosphorylation
- Serine phosphorylation
- τ protein
ASJC Scopus subject areas
- Biochemistry
- Cellular and Molecular Neuroscience