Figure 6. Mmb1p attenuates microtubule dynamics.

(A) Images of mmb1Δ cells expressing mCherry-atb2p and mmb1-GFP^OE. Mmb1-GFP over-expression is variable from cell to cell: low expression (yellow), high expression (red). We chose cells with ~2-folds higher mmb1-GFP fluorescence signal compared to wildtype mmb1-GFP cells to analyze microtubule dynamics. Note that over-expressed mmb1p decorates microtubule lattices strongly (red).

(B) Images of mmb1Δ cells expressing cox4-RFP and mmb1-GFP^OE. Mmb1-GFP over-expression is variable from cell to cell: low expression (yellow), high expression (red). In cells with higher mmb1-GFP signal (red), the mitochondria appear straightened and stretched, consistent with strong binding to microtubules. In cells with lower mmb1-GFP signal (yellow), the mitochondria appear less stretched, consistent with less binding to microtubules. Bar, 5 μm.

(C) Histogram of interphase microtubule bundle numbers for mmb1Δ, wildtype and mmb1^OE cells. Mmb1p does not change the number or organization of interphase microtubules. (D) Box plots showing comparison of microtubule growth and shrinkage rates, and catastrophe and rescue frequencies between mmb1Δ, wildtype and mmb1^OE cells. Mmb1p decreases the shrinkage rate of microtubules. P-values are from Mann-Whitney tests of nonparametric data set. (See also Fig. S6 and Table S1)

(E) Box plot showing comparison of microtubule dynamicity between mmb1Δ, wildtype and mmb1^OE cells. Mmb1p decreases the dynamicity of microtubules. P-values are from Mann-Whitney tests of nonparametric data set. (see also Table S1)