Cryo-EM structures of tau filaments.

•Cryo-EM may be used to determine atomic structures of amyloid filaments extracted from human brain tissue.•Unique protofilament folds characterise tau filaments from different neurodegenerative diseases.•In vitro assembly of recombinant tau with heparin leads to different filaments from those observed in disease.•Isoform composition, post-translational modifications or co-factors may drive structural specificity of tau assembly.