Human Polymerase δ-Interacting Protein 2 (PolDIP2) Inhibits the Formation of Human Tau Oligomers and Fibrils

Abstract

A central characteristic of Alzheimer’s disease (AD) and other tauopathies is the accumulation of aggregated and misfolded Tau deposits in the brain. Tau-targeting therapies for AD have been unsuccessful in patients to date. Here we show that human polymerase δ-interacting protein 2 (PolDIP2) interacts with Tau. With a set of complementary methods, including thioflavin-T-based aggregation kinetic assays, Tau oligomer-specific dot-blot analysis, and single oligomer/fibril analysis by atomic force microscopy, we demonstrate that PolDIP2 inhibits Tau aggregation and amyloid fibril growth in vitro. The identification of PolDIP2 as a potential regulator of cellular Tau aggregation should be considered for future Tau-targeting therapeutics.

Extracellular tau stimulates phagocytosis of living neurons by activated microglia via Toll-like 4 receptor–NLRP3 inflammasome–caspase-1 signalling axis

“…Recombinant human tau protein (2N4R isoform) was expressed in E. coli BL21 Star™ (DE3) strain and purified as described previously 60 . Briefly, tau protein was fused at the N-terminus with His-Sumo tag, purified using Ni +2 ion affinity chromatography.…”

Conformation-Specific Association of Prion Protein Amyloid Aggregates with Tau Protein Monomers

“…Recombinant Tau protein 2N4R isoform was purified as described previously [45] with a difference in one protein expression step. Briefly, pET302/NT-His-SUMO-Tau plazmids were transformed in E. coli BL21(DE3) OneStar cells and cultured on a Petri plate with LB agar supplemented with 50 mg/mL kanamycin and incubated overnight at 37 • C. A colony was inoculated into 50 mL LB supplemented with 50 mg/mL kanamycin and grown overnight at 37 • C. An overnight culture was used for 100-fold inoculation of 3.6 L Terrific Broth (TRB) medium [46] supplemented with 50 mg/mL kanamycin and 1% ethanol [47] which then was incubated at 37 • C until A 600 2.0 and then expression was induced with 2 mM IPTG.…”

“…The resulting medium was incubated at 37 • C for 5 h. Cells were harvested by centrifugation at 6000× g, 4 • C for 30 min. All further purification procedures were completed as described previously [45]. After gelfiltration, Tau protein was exchanged to 50 mM Hepes, pH 7.4 buffer using a HiTrap Desalt column, supplemented with 20 mM NaCl, concentrated to 4 mg/mL and stored at −80 • C. For reactions under different ionic strength conditions, the reaction solutions contained an additional 50 mM, 100 mM or 200 mM NaCl, which was added by replacing a part of the reaction buffer with a 50 mM Hepes buffer (pH 7.4) solution, containing 2 M NaCl.…”

New insights in the molecular regulation of the NADPH oxidase 2 activity: Negative modulation by Poldip2

“…On one hand, Poldip2 appeared to have beneficial functions such as in DNA replication, damage response and repair [3,4,8,18,19], ATP, peptide hormones, and neuropeptides biosynthesis [1,20,21], and cell adhesion [22,23] [6,24,25]. Poldip2 has been also described as playing a crucial role in Tau aggregation [26]. On another hand cellular functions, Poldip2 has been associated with diverse diseases such as cardiac pathologies [27], and breast and lung cancer diseases [28][29][30][31][32] and was shown to be involved in chemo-resistance [33].…”