biostudies-literatureDavies DSThe University of SydneyAustralian National Health and Medical Research Councilbio060067https://www.ebi.ac.uk/biostudies/studies/S-EPMC10924212biostudies-literatureUnknown13(2)Mouse monoclonal 12E8 antibody, which recognises conserved serine phosphorylated KXGS motifs in the microtubule binding domains of tau/tau-like microtubule associated proteins (MAPs), shows elevated binding in brain during normal embryonic development (mammals and birds) and at the early stages of human Alzheimer's disease (AD). It also labels ADF/cofilin-actin rods that form in neurites during exposure to stressors. We aimed to identify direct and indirect 12E8 binding proteins in postnatal mouse brain and embryonic chick brain by immunoprecipitation (IP), mass spectrometry and immunofluorescence. Tau and/or MAP2 were major direct 12E8-binding proteins detected in all IPs, and actin and/or tubulin were co-immunoprecipitated in most samples. Additional proteins were different in mouse versBiology openProtein complexes from mouse and chick brain that interact with phospho-KXGS motif tau/microtubule associated protein antibody.PMC109242122009/GNT0633269Crossett BArthur ATGoldsbury CSAitken HLDavies DSfalseProtein complexes from mouse and chick brain that interact with phospho-KXGS motif tau/microtubule associated protein antibody.Mouse monoclonal 12E8 antibody, which recognises conserved serine phosphorylated KXGS motifs in the microtubule binding domains of tau/tau-like microtubule associated proteins (MAPs), shows elevated binding in brain during normal embryonic development (mammals and birds) and at the early stages of human Alzheimer's disease (AD). It also labels ADF/cofilin-actin rods that form in neurites during exposure to stressors. We aimed to identify direct and indirect 12E8 binding proteins in postnatal mouse brain and embryonic chick brain by immunoprecipitation (IP), mass spectrometry and immunofluorescence. Tau and/or MAP2 were major direct 12E8-binding proteins detected in all IPs, and actin and/or tubulin were co-immunoprecipitated in most samples. Additional proteins were different in mouse vers2024-01-01T00:00:00Z2024 Feb2026-07-15T13:29:34.143Z2026-07-05T03:08:15.398ZS-EPMC109242123829970210.1242/bio.060067