microtubule-binding region (MTBR)-tau243

^[1]^[2]^[3]

Introduction

fragments of tau containing binding region of tau with sites p-tau181, p-tau217, p-tau231 & tau-243
eMTBR-tau243 is an endogenously cleaved tau fragment from the microtubule-binding region (MTBR) that specifically reflects tau tangle pathology in Alzheimer's disease^[1]
MTBR-tau243 refers to the tryptic (enzymatically digested) form of the same tau fragment measured in laboratory assays^[2]
both MTBR-tau243 & eMTBR-tau243 contain residue 243

CSF MTBR-tau243 does not directly represent insoluble tau aggregates, but rather reflects a response to amyloid plaque pathology

CSF MTBR-tau243 is selectively & highly correlated with insoluble tau aggregate pathology
eMTBR-tau243 outperforms tryptic MTBR-tau243 in clinical applications^[3]

↑ ^1.0 ^1.1 Horie K, Salvado G, Koppisetti RK et al Plasma MTBR-tau243 biomarker identifies tau tangle pathology in Alzheimer's disease. Nat Med. 2025 Jun;31(6):2044-2053. PMID: https://pubmed.ncbi.nlm.nih.gov/40164726 PMCID: PMC12176612 Free PMC article. https://pmc.ncbi.nlm.nih.gov/articles/PMC12176612/ https://www.nature.com/articles/s41591-025-03617-7
↑ ^2.0 ^2.1 Horie K, Salvado G, Barthelemy NR et al CSF MTBR-tau243 is a specific biomarker of tau tangle pathology in Alzheimer's disease. Nat Med. 2023 Aug;29(8):1954-1963. PMID: https://pubmed.ncbi.nlm.nih.gov/37443334 PMCID: PMC10427417 Free PMC article. https://pmc.ncbi.nlm.nih.gov/articles/PMC10427417/ https://www.nature.com/articles/s41591-023-02443-z
↑ ^3.0 ^3.1 Devanarayan V, Horie K, Wildsmith K et al Combining CSF MTBR-tau243 and plasma pTau217 ratio enhances the prediction of continuous regional tau PET burden in early Alzheimer's disease. Alzheimers Dement. 2025 Nov;21(11):e70881. PMID: https://pubmed.ncbi.nlm.nih.gov/41170658 PMCID: PMC12576466 Free PMC article. Clinical Trial. https://pmc.ncbi.nlm.nih.gov/articles/PMC12576466/