Identification of novel motifs within TPX2 α5–α7. (A) Domain organization of TPX2 α5–α7 showing newly found motifs. Amino acids 507–523 (cyan) share homology with the SPM, and amino acids 519–531 (orange) and 562–567 (purple) share homology with the γTuNA motif, both of which have a γ-TuRC activation function in the proteins where they were originally identified. Amino acids 620–626 (pink) have been suggested to negatively regulate MT nucleation in Xenopus egg extract, and their absence in X. tropicalis TPX2 leads to increased MT formation. Amino acids 689–716 (blue) are necessary for the interaction between TPX2 and the kinesin Eg5. (B) Graphical representation of the SPM of pericentrin/Spc110 across multiple species and the γTuNA motif of Mto1/centrosomin/CDK5RAP2 and the related myomegalin across multiple species. The motif sequence logos were made using WebLogo 3. Sequence alignment reveals homology between these motifs and sequences within TPX2 α5–α7 (red sequence), revealing the new motifs SPM (cyan box), γTuNAa (orange box), and γTuNAb (purple box). γTuNAa and γTuNAb are separated by a stretch of 29 amino acids.