Modeling mitochondrial transport. (A) Simulation of the decline of mitochondrial quantity that reaches the bud (f_bud) when the dissociation rate from the actin track (k_off) is enhanced. Gray shaded regions indicate normal (MYO2) or increased (myo2(LQ)) k_off rates. For simplicity, we have assumed that daughter cells require at least 15% of the initial mitochondrial mass (blue dashed–dotted line). The dissociation rate k_off is depicted relative to the corresponding association rate, k_on. (B) The distribution of fragmented mitochondria (N_mito) along the mother–bud axis (x) in Δfzo1 cells was simulated as in A and depicted in a time-resolved presentation. The asterisk marks a transient accumulation of mitochondria at the bud neck. (C) 10-fold serial dilutions of myo2(LQ) fzo1-1 cells carrying a vector control (ctrl) or overexpressing YPT11 or ypt11(G40D) from a GPD promoter (OE) were spotted on glucose-containing selective medium and incubated at the indicated temperatures. (D and E) Cells were analyzed as in Fig. 3 (B and C). Bar, 5 µm. (F) Δfzo1 Δmmr1 cells expressing Myo2-Fis1 from the MYO2 promoter on a single-copy plasmid or carrying a vector control (ctrl) were analyzed as in C. Data pooling and statistics are detailed in Table S4.