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Novartis Found Symp

Title:		Outer mitochondrial membrane protein degradation by the proteasome
Author(s):		Neutzner A; Youle RJ; Karbowski M;
Address:		"Biochemistry Section, SNB, NINDS, NIH, Bethesda, MD 20892, USA"
Journal Title:		Novartis Found Symp
Year:		2007
Volume:		287
Issue:
Page Number:		4 - 14
DOI:
ISSN/ISBN:		1528-2511 (Print) 1528-2511 (Linking)
Abstract:		"Protein turnover is used for regulatory processes and to eliminate superfluous, denatured or chemically inactivated polypeptides. Mitochondrial proteins may be particularly susceptible to damage induced by reactive oxygen species and several pathways of mitochondrial proteolysis have been illuminated. However, in contrast to matrix and inner mitochondrial membrane protein degradation, little is known about the turnover of integral outer mitochondrial membrane (OMM) proteins or the mechanisms involved. We have found that pheromone treatment of Saccharomyces cerevisiae induces the proteasome-dependent elimination of the OMM spanning protein, Fzo1, from the mitochondria and that Fzo1 is ubiquitylated while still associated with the membrane. These characteristic processing steps are similar to those of the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway suggesting the term OMMAD, outer mitochondrial membrane-associated degradation, to describe the process. ERAD is dependent upon ER membrane spanning RING domain E3 ubiquitin ligases suggesting that certain E3 ligases in the OMM may also regulate OMMAD. This led us to clone and characterize all 54 predicted human gene products that contain both RING domains and predicted membrane spanning domains. A surprising number of these localize to mitochondria where some may control OMMAD. Some of these mitochondrial RING domain proteins also regulate mitochondrial morphology, indicating a critical role of ubiquitin signalling in the maintenance of mitochondrial homeostasis"
Keywords:		Endoplasmic Reticulum/*metabolism Membrane Proteins/*metabolism Mitochondria/*metabolism Mitochondrial Membranes/*metabolism Mitochondrial Proteins/*metabolism Proteasome Endopeptidase Complex/*pharmacology Saccharomyces cerevisiae/growth & development Sa;
Notes:		"MedlineNeutzner, Albert Youle, Richard J Karbowski, Mariusz eng Review England 2007/12/14 Novartis Found Symp. 2007; 287:4-14; discussion 14-20"