AtCCMA interacts with AtCcmB to form a novel mitochondrial ABC transporter involved in cytochrome c maturation in Arabidopsis.
ABC transporters make a large and diverse family of proteins found in all phylae. AtCCMA is the nucleotide binding domain of a novel Arabidopsis mitochondrial ABC transporter. It is encoded in the nucleus and imported into mitochondria. Sub-organellar and topology studies find AtCCMA bound to the mitochondrial inner membrane, facing the matrix. AtCCMA exhibits an ATPase activity, and ATP/Mg(2+) can facilitate its dissociation from membranes. Blue Native PAGE shows that it is part of a 480-kDa complex. Yeast two-hybrid assays reveal interactions between AtCCMA and domains of CcmB, the mitochondria-encoded transmembrane protein of a conserved ABC transporter. All these properties designate the protein as the ortholog in plant mitochondria of the bacterial CcmA required for cytochrome c maturation. The transporter that involves AtCCMA defines a new category of eukaryotic ABC proteins because its transmembrane and nucleotide binding domains are encoded by separate genomes.
Rayapuram
Naganand
N
Institut de Biologie Moléculaire des Plantes du CNRS, Université Louis Pasteur, 67084 Strasbourg, France.
Hagenmuller
Jérémie
J
Grienenberger
Jean-Michel
JM
Giegé
Philippe
P
Bonnard
Géraldine
G
D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000502:physiology*; D003001:Cloning, Molecular; D045304:Cytochromes c / Q000378:metabolism*; D018745:Genome, Plant; D008274:Magnesium / Q000737:chemistry; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; C522740:CcmA protein, Arabidopsis; D000255:Adenosine Triphosphate; D045304:Cytochromes c; D008274:Magnesium