The objective of this Comment paper is to highlight a critical point leading the authors to the suggestion as follows: “the central folded domain of TPPP/p25 following binding to microtubules can drive homotypic protein-protein interactions leading to bundled microtubules” (cf. Abstract)1. In fact, this hypothesis is based upon the observation that: “Our biophysical analysis of all the fragments though did not support the formation of TPPP/p25 dimers in solution” (page 11). Our biochemical, biophysical and immunological Please change analysis to analyses. have provided evidence for concentration-dependent dimerization of TPPP/p25 in the absence of MTs4, however, it is promoted by the presence of ligands such as GTP4 and the bivalent zinc ion8. We have also established the role of intermolecular disulphide bridges in the stabilization of the dimers4, and that in the presence of dithioerythritol (DTE) (its epimer, DTT was used in the commented paper) the detection of the dimer forms is ambiguous48. In the experiments presented in Skoufias’s paper1, DTT (1 mM) is present in the TPPP/p25 solutions including the stored stock solutions and the solutions used for the binding and polymerization assays. This condition favours neither the detection of the dimeric form nor the dimer-enhanced tubulin polymerization activity resulting in low polymerization potency (cf. Fig. 1C of ref. 1 versus Fig. 3B of ref. 5). In order to enhance the relative amount of the disulphide-stabilized dimers, in selected experiments the stock solutions of TPPP/p25 (200 μM) were pre-incubated at room temperature, and the dimers could be detected even by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) (cf. Fig. 1) as demonstrated earlier4.