MOM19, an import receptor for mitochondrial precursor proteins.
We have identified a 19 kd protein of the mitochondrial outer membrane (MOM19). Monospecific IgG and Fab fragments directed against MOM19 inhibit import of precursor proteins destined for the various mitochondrial subcompartments, including porin, cytochrome c1, Fe/S protein, F0 ATPase subunit 9, and F1 ATPase subunit beta. Inhibition occurs at the level of high affinity binding of precursors to mitochondria. Consistent with previous functional studies that suggested the existence of distinct import sites for ADP/ATP carrier and cytochrome c, we find that import of those precursors is not inhibited. We conclude that MOM19 is identical to, or closely associated with, a specific mitochondrial import receptor.
Söllner
T
T
Institut für Physiologische Chemie, Universität München, Federal Republic of Germany.
Griffiths
G
G
Pfaller
R
R
Pfanner
N
N
Neupert
W
W
D000818:Animals; D000906:Antibodies; D000936:Antigen-Antibody Complex; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D009491:Neurospora / Q000378:metabolism*; D009492:Neurospora crassa / Q000378:metabolism*; D018272:Porins; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000032:analysis / Q000378:metabolism*; D012156:Reticulocytes / Q000378:metabolism; D013367:Submitochondrial Particles
D000906:Antibodies; D000936:Antigen-Antibody Complex; D001425:Bacterial Outer Membrane Proteins; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D008565:Membrane Proteins; D018272:Porins; D011498:Protein Precursors; D011956:Receptors, Cell Surface