Abstract
FtsH, also called AAA protease, is a membrne-bound ATP-dependent metalloprotease and present in chloroplasts and mitochondria in plants. In mitochondria, several homologues have been identified in inner membranes with its catalytic domain faced either to matrix (m-AAA) or to intermembrane space (i-AAA). We have shown that in Arabidopsis, twelve potential FtsHs are present and that three are targeted into mitochondria. Moreover, a recent study indicated that one of the homologues FtsH11 is dual-targeted into chloroplasts and mitochondria. The overall results demonstrated that four FtsHs, two m-AAAs (FtsH3 and 10) and two i-AAAs (FtsH4 and 11) are present in Arabidopsis mitochondria. We isolated T-DNA insertion mutants for these four FtsH genes. Homozygous mutants were successfully isolated for all genes, suggesting that loss of one of the mitochondrial homologues is dispensable. We are currently generating double mutants, and initial characterization of the double mutants will be presented.
