Plant β-tubulin phosphorylation on Ser172 as canonical suppressing factor of microtubule growth

Abstract

Aim. The estimation of potential role of plant β-tubulin Ser172 phosphorylation for correct function of microtubules and cell division due to selection of protein kinases, most probable associated with phosphorylation of Ser172 in Arabidopsis thaliana (L.) Heynh. Methods. Literature and database search. Comparison of protein sequences and structures: multiple sequence alignment, phylogenetic profiling, protein structure modeling, etc. Results. Comparison of Ser172 site region from all known β-tubulins from Homo sapiens, Sus scrofa, Saccharomyces cerevisiae, Drosophila melanogaster and A. thaliana confirms its significant similarity. Joint clusterization of all Ser172 site regions (in S±10 a.a. format) reveals that plant site is most similar to Ser172±10 fragment of β-tubulin from S. cerevisiae. At the same time, sequences and catalytic domain structures of cyclin-dependent kinases 1 and YAK1-related kinases (MNB/DYRK1a/YAK1) associated with Ser172 phosphorylation, found maximal similarity in A. thaliana and S. cerevisiae. Сonclusions. The results confirm similarity of amino acid environment of Ser172 in β-tubulin isotypes in human, pig, fruit fly, yeast and arabidopsis. This suggests similar effect of β-tu­bulin phosphorylation at Ser172 for inhibition of microtubule assembly onto their protofilaments and its association with CDK1 and YAK1-related protein kinases. Similarity of Ser172 sites and associated protein kinases, allows us to expect similar effect of this modification on structure of microtubules in A. thaliana and S. cerevisiae. Keywords: β-tubulin, Ser172, phospho­rylation, CDK1, DYRK1, MNB, YAK1.