The mitochondrial proteins AtHscB and AtIsu1 involved in Fe-S cluster assembly interact with the Hsp70-type chaperon AtHscA2 and modulate its catalytic activity

Mitochondrion. 2014 Nov:19 Pt B:375-81. doi: 10.1016/j.mito.2014.11.002. Epub 2014 Nov 15.

Abstract

Arabidopsis plants contain two genes coding for mitochondrial Hsp70-type chaperon-like proteins, AtHscA1 (At4g37910) and AtHscA2 (At5g09590). Both genes are homologs of the Ssq1 gene involved in Fe-S cluster assembly in yeast. Protein-protein interaction studies showed that AtHscA2 interacts with AtIsu1 and AtHscB, two Arabidopsis homologs of the Isu1 protein and the Jac1 yeast co-chaperone. Moreover, this interaction could modulate the activity of AtHscA2. In the presence of a 1:5:5 molar ratio of AtHscA2:AtIsu1:AtHscB we observed an increase in the V(max) and a decrease in the S(0.5) for ATP of AtHscA2. Furthermore, an increase of about 28-fold in the catalytic efficiency of AtHscA2 was also observed. Results suggest that AtHscA2 in cooperation with AtIsu1 and AtHscB play an important role in the regulation of the Fe-S assembly pathway in plant mitochondria.

Keywords: Arabidopsis; Fe–S clusters; Hsp70-like; Mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / cytology
  • Arabidopsis / enzymology*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / metabolism*
  • Metabolic Networks and Pathways
  • Mitochondria / enzymology
  • Mitochondria / metabolism
  • Mitochondrial Proteins / metabolism*
  • Protein Binding
  • Protein Interaction Mapping

Substances

  • Arabidopsis Proteins
  • HscA2 protein, Arabidopsis
  • HscB protein, Arabidopsis
  • ISU1 protein, A thaliana
  • Mitochondrial Proteins