Mgm1 is a positive regulator of mitochondrial–nuclear heme trafficking. Heme trafficking rates were monitored using the SA pulse-chase assay and rate constants calculated, as described in Fig. 2, for (A,B) mgm1Δ, (C,D) rho0, (E,F) fzo1Δ, (G,H) ugo1Δ, (I,J) pcp1Δ cells and (K,L) mic60Δ cells. Data represent the mean±s.d. of independent triplicate cultures. *P<0.05 (one-way ANOVA with Dunnett's post-hoc test).