TTBK1

Tau tubulin kinase 1 (TTBK1) belongs to the CK1 group of the kinome and phosphorylates both tau protein and β-tubulin at proline-directed Ser/Thr motifs. It is enriched in brain, where TTBK1 has been proposed to contribute to tau hyperphosphorylation in Alzheimer disease, and it also acts in ciliogenesis and cell-cycle progression. Structurally, TTBK1 combines an N-terminal catalytic domain with a large C-terminal proline-rich tail. Its paralog TTBK2 differs by regulating ciliary trafficking and causing spinocerebellar ataxia. Because recombinant TTBK1 is active on tau substrates, it is widely used for kinase assays and inhibitor profiling in tauopathy research.