Details of tubulin-bound Kip2-MD homology model and effects of indicated mutants in heterozygous yeast cells. (A) Kip2-MD homology model (blue) in complex with a αβ-tubulin (gray) heterodimer. The three positively charged Kip2-MD surface patches that are crucial for tubulin or microtubule binding are highlighted in different colors (see corresponding legend). (B) Predicted binding of Kip2-MD (blue) to the curved (brown) and straight (gray) conformational states of tubulin. Residues K294 and R296 (P1, purple) and R446 (P3, sky blue) are highlighted to illustrate that P1 may selectively bind to the curved conformation of tubulin. (C) Localization of the wild-type and the tubulin-binding patch mutants of Kip2 in heterozygous diploid cells. Representative images of preanaphase heterozygous diploid cells expressing wild-type and tubulin-binding patch mutants of Kip2 fused to 3xsfGFP (green), together with wild-type Kip2 fused to mCherry. SPBs are visualized with Spc42-mCherry (magenta). Scale bars, 2 μm.