A PCBP1-BolA2 chaperone complex delivers iron for cytosolic [2Fe-2S] cluster assembly

Area of Science:

• Biochemistry
• Cellular Biology
• Molecular Biology

Background:

• Cellular proteins rely on iron cofactors for function.
• The poly(rC)-binding protein (PCBP) family is crucial for distributing ferrous ions.
• The precise mechanisms of cytosolic iron handling remain incompletely understood.

Purpose of the Study:

• To elucidate the molecular details of cytosolic iron distribution.
• To identify proteins involved in iron cofactor assembly.
• To understand the link between ferrous iron and iron-sulfur cluster distribution systems.

Main Methods:

• In vitro and cellular biochemical analyses.
• Proteomics to identify PCBP1-interacting proteins.
• Characterization of protein-protein and protein-ligand interactions.

Main Results:

• PCBP1 coordinates iron using cysteine, glutamate, and glutathione (GSH).
• BolA2, complexed with Glrx3, acts as a cytosolic [2Fe-2S] cluster chaperone.
• PCBP1-Fe-GSH forms a complex with BolA2, facilitating [2Fe-2S] cluster assembly on BolA2-Glrx3.

Conclusions:

• PCBP1-Fe-GSH-BolA2 is a key intermediate complex.
• This complex links cellular ferrous iron and iron-sulfur cluster distribution pathways.
• Provides molecular insight into iron cofactor biogenesis.