By examining six brain regions at single-molecule resolution, researchers identified a layer of tau pathology that conventional tissue staining could not fully capture. Study: Nanoscopic tau aggregates in Parkinson’s disease. Image Credit: peterschreiber.media / Shutterstock In a recent study published online as an 'article in press' in the journal npj Parkinson's Disease, researchers used single-molecule pull-down (SiMPull) assays and super-resolution microscopy to map nanoscopic distributions of protein aggregates in post-mortem human brain tissue. The study specifically analyzed six distinct brain regions using tissue from 29 post-mortem donors, although sample availability varied by region, and identified a distinct population of high-intensity, nanoscopic phosphorylated tau (pTau) aggregates in the putamen of Parkinson's disease (PD) cases. The putamen is a region where standard immunohistochemistry showed negligible tau staining in this cohort. The study further revealed that these nanoscopic tau aggregates ranged in length from 30 to 800 nanometers, while pTau intensity was inversely correlated with alpha-synuclein (αSyn) immunohistochemical coverage in the amygdala. Furthermore, tau aggregate burden was highest on average among the five PD cases with recorded dementia, whereas single-molecule assays did not identify a PD-specific population of nanoscopic αSyn species. Background Classical neuropathological evaluation of Parkinson's disease (PD) typically focuses on alpha-synuclein...

Phospholipids function as signaling molecules regulating numerous processes within the cellular environment. Identifying and characterizing the protein players involved in lipid-mediated functions remains a central focus. Here, we present a protocol for evaluating lipid-protein interactions using mammalian whole-cell lysates expressing proteins of interest in a single-molecule pull-down (SiMPull) assay. We describe steps for preparing materials and slide chambers, performing SiMPull, and analyzi...