Phospho-Tau (Ser422) Antibody [L19H1]

Application: Reactivity: Human

Usage Information

Dilution
WB1:10000 - 1:20000

Application
WB

Reactivity
Human

Source
Rabbit Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW Observed MW
50-100 kDa 55 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight.

Positive Control	IMR-32 cells; SH-SY5Y cells (Okadiac acid and calyculin A treated)
Negative Control	SH-SY5Y cells; IMR-32 (phosphatase treated)

Datasheet & SDS

Biological Description

Specificity
Phospho-Tau (Ser422) Antibody [L19H1] detects endogenous levels of total Tau protein only when it is phosphorylated at Ser422.

Clone
L19H1

Synonym(s)
MAPT; Microtubule-associated protein tau; Neurofibrillary tangle protein; Paired helical filament-tau; PHF-tau

Background
Phospho-Tau (Ser422) is a disease-associated post-translational modification of the microtubule-associated protein Tau (MAPT), one of six brain isoforms (~352–441 aa) that normally stabilizes axonal microtubules via its N-terminal projection domain, proline-rich region (P1/P2 motifs), four microtubule-binding repeats (R1–R4), and C-terminal tail. Ser422 resides in the R2 repeat flanking the KXGS motifs critical for tubulin binding; phosphorylation at pSer422 (mimicked by S422E pseudophosphorylation) enhances SDS-stable dimer formation, prolongs aggregation nucleation, exposes the phosphatase-activating domain (PAD, aa 2-18), and alters tau conformers without changing total aggregate yield. pSer422 tau monomers inhibit anterograde kinesin-1-dependent fast axonal transport (FAT), while its aggregates uniquely block both anterograde and retrograde FAT, unlike unmodified tau, disrupting axonal trafficking of vesicles, mitochondria, and signaling molecules essential for neuronal viability. This modification correlates with cognitive decline, neuropil threads, and oligomeric tau in prodromal Alzheimer's disease (AD) brain, activating PP1-GSK3β pathways that exacerbate microtubule disassembly, synaptic loss, and neurodegeneration in tauopathies.

Background

Phospho-Tau (Ser422) is a disease-associated post-translational modification of the microtubule-associated protein Tau (MAPT), one of six brain isoforms (~352–441 aa) that normally stabilizes axonal microtubules via its N-terminal projection domain, proline-rich region (P1/P2 motifs), four microtubule-binding repeats (R1–R4), and C-terminal tail. Ser422 resides in the R2 repeat flanking the KXGS motifs critical for tubulin binding; phosphorylation at pSer422 (mimicked by S422E pseudophosphorylation) enhances SDS-stable dimer formation, prolongs aggregation nucleation, exposes the phosphatase-activating domain (PAD, aa 2-18), and alters tau conformers without changing total aggregate yield. pSer422 tau monomers inhibit anterograde kinesin-1-dependent fast axonal transport (FAT), while its aggregates uniquely block both anterograde and retrograde FAT, unlike unmodified tau, disrupting axonal trafficking of vesicles, mitochondria, and signaling molecules essential for neuronal viability. This modification correlates with cognitive decline, neuropil threads, and oligomeric tau in prodromal Alzheimer's disease (AD) brain, activating PP1-GSK3β pathways that exacerbate microtubule disassembly, synaptic loss, and neurodegeneration in tauopathies.

References
https://pubmed.ncbi.nlm.nih.gov/27373205/ https://pubmed.ncbi.nlm.nih.gov/22690349/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%