Updated project metadata. The microtubule network is formed from polymerised tubulin subunits and associating proteins, which govern microtubule dynamics and a diverse array of functions. To identify novel microtubule binding proteins, we have developed an unbiased biochemical assay which relies on the selective extraction of cytosolic proteins from cells, whilst leaving behind the microtubule network. Candidate proteins are linked to microtubules by their sensitivities to the depolymerising drug nocodazole or the microtubule stabilising drug, taxol, which are then quantitated in a triplex experiment. Our approach is first benchmarked by co-segregation of tubulin and previously established microtubule-binding proteins. We then identify several novel candidate microtubule binding proteins. Amongst these, we have selected the ubiquitin E3 ligase TRIM3 (Tripartite motif-containing protein 3) for further characterisation. TRIM3 binding to microtubules is mapped to its C-terminal NHL-repeat region. We show that TRIM3 is required for the rapid accumulation of acetylated tubulin, following treatment with the microtubule stabilising drug taxol. Furthermore, loss of TRIM3, partially recapitulates the reduction in nocodozole resistant microtubules characteristic of Alpha Tubulin Acetyltransferase 1 (ATAT1) depletion. These results can be explained by a decrease in ATAT1 that follows depletion of TRIM3 that is independent of transcription.