The tektin family of microtubule-stabilizing proteins

Abstract

Protein family reviewT Th he e t te ek kt ti in n f fa am mi il ly y o of f m mi ic cr ro ot tu ub bu ul le e--s st ta ab bi il li iz zi in ng g p pr ro ot te ei in ns s Linda A Amos Address: MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK. Email: laa@mrc-lmb.cam.ac.uk S Su um mm ma ar ry yTektins are insoluble α-helical proteins essential for the construction of cilia and flagella and are found throughout the eukaryotes apart from higher plants. Being almost universal but still fairly free to mutate, their coding sequences have proved useful for estimating the evolutionary relationships between closely related species. Their protein molecular structure, typically consisting of four coiled-coil rod segments connected by linkers, resembles that of intermediate filament (IF) proteins and lamins. Tektins assemble into continuous rods 2 nm in diameter that are probably equivalent to subfilaments of the 10 nm diameter IFs. Tektin and IF rod sequences both have a repeating pattern of charged amino acids superimposed on the seven-amino-acid hydrophobic pattern of coiled-coil proteins. The length of the repeat segment matches that of tubulin subunits, suggesting that tektins and tubulins may have coevolved, and that lamins and IFs may have emerged later as modified forms of tektin. Unlike IFs, tektin sequences include one copy of a conserved peptide of nine amino acids that may bind tubulin. The 2 nm filaments associate closely with tubulin in doublet and triplet microtubules of axonemes and centrioles, respectively, and help to stabilize these structures. Their supply restricts the assembled lengths of cilia and flagella. In doublet microtubules, the 2 nm filaments may also help to organize the longitudinal spacing of accessory structures, such as groups of inner dynein arms and radial spokes. The electronic version of this article is the complete one and can be found online at

Enriched variations in TEKT4 and breast cancer resistance to paclitaxel

“…For patients carrying these two germline variations in TEKT4, taxanes may have limited efficacy. Tektins associate closely with tubulin in doublet microtubules via direct, tight and specific interactions 22 . In doublet microtubules, tektins also help to organize the longitudinal spacing of accessory structures, such as groups of inner dynein arms and radial spokes 21 .…”

“…Compared with blood DNA, both of the two pre-treatment tumour samples showed LOH. Tektin4 belongs to the tektin family, which associates closely with tubulin in doublet microtubules and helps stabilize these structures 21,22 . We subsequently examined the frequency of enriched TEKT variations in an independent extension cohort of 84 paired samples of different molecular subtypes (clinicopathologic characteristics are listed in Table 2).…”

Cep57 Protein Is Required for Cytokinesis by Facilitating Central Spindle Microtubule Organization

“…4 and 5). Tektin 1 belongs to a conserved Tektin protein family, which includes several coiled-coil proteins and which is involved in many developmental processes, such as fertilization (25). Studies on sperm flagella from sea urchin suggested that Tektin proteins may interact with the plus-ends of doublet microtubules and be related to the control of axonemal length (25).…”

“…Tektin 1 belongs to a conserved Tektin protein family, which includes several coiled-coil proteins and which is involved in many developmental processes, such as fertilization (25). Studies on sperm flagella from sea urchin suggested that Tektin proteins may interact with the plus-ends of doublet microtubules and be related to the control of axonemal length (25). Therefore, Cep57 and Tektin 1 might have a cooperative function in the organization of the overlapping microtubule plus-ends at the central spindle and midbody, suggesting that the function of Cep57 in microtubule-bundling activity also could be related to its interacting proteins.…”

“…Tektin 1, a structural component of axonemal doublet microtubules in cilia and flagella (25,26), was identified as a Cep57-binding protein (supplemental Fig. S2A).…”