Figure S1.
Cik1-Kar3 promotes shmoo tip microtubule bundle dynamics without affecting polymerization and depolymerization speed.(A) Diagram describing microtubule bundle dynamics in an α-factor–arrested cell. Cycles of bundle shrinkage and growth cause pulling and pushing of the nucleus toward and away from the shmoo tip. (B) Representative image of a polarized cell. The dotted white rectangle includes the microtubule bundle between the shmoo tip and the SPB. Below, a montage of the area is shown; 25 consecutive frames with 5-s time intervals. Scale bar is 1 µm. (C) Fluorescence micrographs showing colocalization of Kar3 and Stu2 to individual plus ends (depicted by arrowheads) in the shmoo tip bundle. Scale bar is 2 µm; in magnified inset, scale bar is 1 µm. (D) Examples for scoring for shmoo tip alignment defects. Bundle was scored as misaligned when growing Stu2-mRuby2 comets deviated >45° from the SPB to the shmoo tip axis. Arrows point to aligned versus misaligned microtubules. Scale bar is 2 µm. (E) Kymographs from a 5-min-long movie of a wild-type and Kar3-AID + NAA cell are shown. The triangles show Δx and Δy as an example for how bundle dynamics values were acquired (1 = depolymerization; 2 = polymerization). Number of cases when at least one microtubule was misaligned during movie acquisition is shown above the kymographs. Scale bars are 0.5 µm. Immunoblotting shows time course and efficiency of Kar3-AID depletion after addition of 1 mM NAA in exponentially growing and α-factor–arrested cells. α-PGK, anti-Phospho-glycerol kinase blot as loading control. (F) Individual nuclear microtubules are highly dynamic. α-Factor–arrested cells expressing Stu2-GFP were followed by live-cell microscopy. Arrowheads point to individual microtubule plus ends. Kymographs from 2-min high time-resolution movies of Stu2-GFP. Upper panel shows a single individual microtubule; bottom panel has several microtubules replacing each other. Dashed lines show one polymerization cycle. Scale bar is 1 µm. (G) Parameters of dynamics of individual microtubules (top row) and MT bundles (three bottom rows) are listed in the table. pol, polymerization; depol, depolymerization; cat, catastrophe. Parameters that differ from others are highlighted in red. Experiments were repeated at least three times, and means ± SD are shown. N.A., nonapplicable.

Cik1-Kar3 promotes shmoo tip microtubule bundle dynamics without affecting polymerization and depolymerization speed. (A) Diagram describing microtubule bundle dynamics in an α-factor–arrested cell. Cycles of bundle shrinkage and growth cause pulling and pushing of the nucleus toward and away from the shmoo tip. (B) Representative image of a polarized cell. The dotted white rectangle includes the microtubule bundle between the shmoo tip and the SPB. Below, a montage of the area is shown; 25 consecutive frames with 5-s time intervals. Scale bar is 1 µm. (C) Fluorescence micrographs showing colocalization of Kar3 and Stu2 to individual plus ends (depicted by arrowheads) in the shmoo tip bundle. Scale bar is 2 µm; in magnified inset, scale bar is 1 µm. (D) Examples for scoring for shmoo tip alignment defects. Bundle was scored as misaligned when growing Stu2-mRuby2 comets deviated >45° from the SPB to the shmoo tip axis. Arrows point to aligned versus misaligned microtubules. Scale bar is 2 µm. (E) Kymographs from a 5-min-long movie of a wild-type and Kar3-AID + NAA cell are shown. The triangles show Δx and Δy as an example for how bundle dynamics values were acquired (1 = depolymerization; 2 = polymerization). Number of cases when at least one microtubule was misaligned during movie acquisition is shown above the kymographs. Scale bars are 0.5 µm. Immunoblotting shows time course and efficiency of Kar3-AID depletion after addition of 1 mM NAA in exponentially growing and α-factor–arrested cells. α-PGK, anti-Phospho-glycerol kinase blot as loading control. (F) Individual nuclear microtubules are highly dynamic. α-Factor–arrested cells expressing Stu2-GFP were followed by live-cell microscopy. Arrowheads point to individual microtubule plus ends. Kymographs from 2-min high time-resolution movies of Stu2-GFP. Upper panel shows a single individual microtubule; bottom panel has several microtubules replacing each other. Dashed lines show one polymerization cycle. Scale bar is 1 µm. (G) Parameters of dynamics of individual microtubules (top row) and MT bundles (three bottom rows) are listed in the table. pol, polymerization; depol, depolymerization; cat, catastrophe. Parameters that differ from others are highlighted in red. Experiments were repeated at least three times, and means ± SD are shown. N.A., nonapplicable.

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