J. Biol. Chem., Vol. 261, Issue 25, 11440-11443, Sep, 1986
A mitochondrial presequence can transport a chloroplast-encoded protein into yeast mitochondria
EC Hurt, M Goldschmidt-Clermont, B Pesold-Hurt, JD Rochaix and G Schatz
Ribulose-1,5-bisphosphate carboxylase/oxygenase of chloroplasts contains
eight large and eight small subunits. The small subunit is encoded by
nuclear DNA, synthesized in the cytoplasm, and imported into chloroplasts.
The large subunit is encoded by chloroplast DNA and synthesized within
chloroplasts. We show in this communication that the large subunit of
Chlamydomonas chloroplasts could be efficiently imported into isolated
yeast mitochondria if it was attached to the presequence of a protein
transported into the yeast mitochondrial matrix. Thus, synthesis of the
large subunit within chloroplasts does not reflect the inability of this
subunit to cross membranes. The same mitochondrial presequence could also
transport the nuclear-encoded small subunit into yeast mitochondria.
However, when the two types of subunits were coimported into mitochondria,
they did not assemble with each other inside the heterologous organelle.