Dear Editor,

Microtubules consisting of α/β-tubulin dimers exhibit various shapes in different cell stages and cell types, which are important for their diverse roles in eukaryotic cells. Both α- and β-tubulin comprise multiple genes in vertebrates, e.g. mice have at least seven α-tubulin and eight β-tubulin genes. The distribution and expression of these isotypes vary widely among different tissues and developmental stages. Tubulin α1A is generally expressed in post-mitotic neurons and exhibits a decrease in postnatal and adult stages (Yue et al., 2014), while tubulin α4A is highly expressed in the brain and heart during later stages of development (Yue et al., 2014). In vitro studies have shown that purified recombinant α/β3 microtubules display a higher catastrophe frequency than α/β2B microtubules (Pamula et al., 2016), and GMPCPP-α1B/β2B microtubules are more stable and have more protofilaments than GMPCPP-α1B/β3 (Ti et al., 2018), suggesting that some tubulin isotypes affect microtubule properties. However, the effects of specific α-tubulin isotype on microtubule properties remain largely unknown.