Association of rho proteins with the mitochondria organelle

The proteins of the rho gene family have been isolated from cytosolic as well as particulate fractions. The rho proteins have values of about 22KDa and have consensus amino acid sequences for GTP/GDP-binding and GTPase activities. We have localized the rho proteins in mammalian cells by using affinity-purified anti-peptide antibodies in immunofluorescence and immunoelectron microscopy studies. The majority of rho appears to be concentrated in the mitochondrial membranes while a small fraction is seen in the cytoplasm and in the cytosolic lysosomal compartments, suggesting that rho protein(s) might be involved in the mitochondrial function or assembly.