Table 4.

Experimental validation of the predictions and suggested experiments. See text for details on the suggested experiments.

Prediction	Experimental Validation	Suggested experiments
Grx5 acts in recovering the activity of Nfs1 or of the scaffold proteins	Experimentally detected interaction with the scaffolds [34]	Use of kinetic assays and TAP assays to pinpoint the most likely targets for Grx5
Arh1-Yah1 act on S or ST	Yes [73, 74]
Arh1-Yah1 interact in a similar way to their bovine homologues	No	Point Mutants and use of TAP assays combined with measurements of ISC dependent protein activity and Fe accumulation in mutant strains
Yfh1 acts on S, T or ST	Yes [76-79]
Yfh1 storage of Fe is not important for its ISC biogenesis role	Yes [86]
Nfs1 role in synthesis is sufficient to justify Δnfs1 phenotype	No
Chaperone role in F or St	Yes for F [94]	In vitro systems with and without chaperones to compare rate of assembly of ISC onto the scaffold would provide some evidence for or against St.