Figure 5.

Fe/S cluster assembly on Nar1p depends on the mitochondrial ISC machinery. (A) Wild-type and the galactose-regulatable Gal-NFS1, Gal-YAH1 and Gal-ATM1 cells were transformed with plasmid p426-NAR1 (Nar1↑) or empty vector p426 (−). Cells were grown in iron-poor medium supplemented with galactose (Gal) or glucose (Glu) for 24 h. Cells were radiolabelled with ⁵⁵Fe and disrupted with glass beads in Triton X-100-containing buffer. Nar1p was isolated from the cell extract by immunoprecipitation and the amount of ⁵⁵Fe associated with Nar1p was quantified by scintillation counting. The indicated proteins were visualised by immunostaining of cell extracts. (B) The indicated cells overproducing Nar1p were grown for 40 h and cell extracts were analysed as in (A).