The working mechanism of the DCX domain in DCX-EMAP. (A) The predicted structure of the DCX domain of DCX-EMAP (residues: 164–383; upper panel) and human DCX (residues: 32–276; lower panel). The protein structure model of DCX-EMAP (UniProt: Q9VUI3) and human DCX (UniProt: O43602) were derived from the AlphaFold Protein Structure Database. (B) SDS-PAGE analysis (Coomassie blue staining) of purified fly S2 tubulin (Lane 1: 1.25 μg protein. Lane 2: 5 μg protein). (C) SDS-PAGE analysis (Coomassie blue staining) of purified DCX1/2 (lane 1), DCX1 (lane 2), and DCX2 (lane 3). (D) Representative confocal images showing that when full-length GFP-DCX-EMAP and mCherry-ΔDCX1/2 were co-expressed in S2 cells, no colocalization was observed. Scale bar, 10 µm. (E) Representative confocal images showing the microtubule-associated signals of HA-DCX-EMAP and HA-ΔDCX1/2 in S2 cells. Scale bar, 10 µm. (F) Sequence alignment of the TAPE domain of the EMAP family members (fly DCX-EMAP, C.elegans ELP-1, and human EML1-4). The key residues in the R-patch (blue) and hydrophobic clamp (green) are indicated in the aligned sequence. (G) Molecular details of the microtubule-interaction interfaces in the β-propeller of TAPE domain in EML2S and DCX-EMAP. Blue: Basic residue. White: Hydrophobic residues. Red: Hydrophilic residues. Source data are available for this figure: SourceData FS5.