Regulation of 2-oxoglutarate (alpha-ketoglutarate) dehydrogenase stability by the RING finger ubiquitin ligase Siah.
The 2-oxoglutarate dehydrogenase complex (OGHDC) (also known as the alpha-ketoglutarate dehydrogenase complex) is a rate-limiting enzyme in the mitochondrial Krebs cycle. Here we report that the RING finger ubiquitin-protein isopeptide ligase Siah2 binds to and targets OGDHC-E2 for ubiquitination-dependent degradation. OGDHC-E2 expression and activity are elevated in Siah2(-/-) cells compared with Siah2(+)(/)(+) cells. Deletion of the mitochondrial targeting sequence of OGDHC-E2 results in its cytoplasmic localization and rapid proteasome-dependent degradation in Siah2(+)(/)(+) but not in Siah2(-/-) cells. Significantly, because of its overexpression or disruption of the mitochondrial membrane potential, the release of OGDHC-E2 from mitochondria to the cytoplasm also results in its concomitant degradation. The role of the Siah family of ligases in the regulation of OGDHC-E2 stability is expected to take place under pathological conditions in which the levels of OGDHC-E2 are altered.
Habelhah
Hasem
H
Department of Oncological Sciences, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, USA.
Laine
Aaron
A
Erdjument-Bromage
Hediye
H
Tempst
Paul
P
Gershwin
M Eric
ME
Bowtell
David D L
DD
Ronai
Ze'ev
Z
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D007655:Ketoglutarate Dehydrogenase Complex / Q000737:chemistry / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials; D051379:Mice; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D009687:Nuclear Proteins; D010957:Plasmids / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D014162:Transfection; D019076:Transgenes; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry*; D000098563:Seven in Absentia Proteins
D009687:Nuclear Proteins; D014157:Transcription Factors; D025801:Ubiquitin; D007655:Ketoglutarate Dehydrogenase Complex; D044767:Ubiquitin-Protein Ligases; D000098563:Seven in Absentia Proteins; D046988:Proteasome Endopeptidase Complex