Sequential action of two hsp70 complexes during protein import into mitochondria.
The mitochondrial chaperone mhsp70 mediates protein transport across the inner membrane and protein folding in the matrix. These two reactions are effected by two different mhsp70 complexes. The ADP conformation of mhsp70 favors formation of a complex on the inner membrane; this 'import complex' contains mhsp70, its membrane anchor Tim44 and the nucleotide exchange factor mGrpE. The ATP conformation of mhsp70 favors formation of a complex in the matrix; this 'folding complex' contains mhsp70, the mitochondrial DnaJ homolog Mdj1 and mGrpE. A precursor protein entering the matrix interacts first with the import complex and then with the folding complex. A chaperone can thus function as part of two different complexes within the same organelle.
Horst
M
M
Biozentrum, Universität Basel, Switzerland.
Oppliger
W
W
Rospert
S
S
Schönfeld
H J
HJ
Schatz
G
G
Azem
A
A
D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D005493:Folic Acid Antagonists / Q000494:pharmacology; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006639:Histidine; D007425:Intracellular Membranes; D007770:L-Lactate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D042844:L-Lactate Dehydrogenase (Cytochrome); D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008727:Methotrexate / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D018832:Molecular Chaperones; D010455:Peptides; D011485:Protein Binding; D017510:Protein Folding; D011498:Protein Precursors / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics / Q000378:metabolism
D002352:Carrier Proteins; D005493:Folic Acid Antagonists; D005656:Fungal Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C087041:MDJ1 protein, S cerevisiae; C086039:MGE1 protein, S cerevisiae; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D018832:Molecular Chaperones; D010455:Peptides; D011498:Protein Precursors; D029701:Saccharomyces cerevisiae Proteins; C077016:TIM44 protein, S cerevisiae; C033223:polyhistidine; D006639:Histidine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; D042844:L-Lactate Dehydrogenase (Cytochrome); D013762:Tetrahydrofolate Dehydrogenase; D000251:Adenosine Triphosphatases; D008727:Methotrexate