Searching across hundreds of databases

Our searching services are busy right now. Your search will reload in five seconds.

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Formation of membrane-bound ring complexes by prohibitins in mitochondria.

Prohibitins comprise a remarkably conserved protein family in eukaryotic cells with proposed functions in cell cycle progression, senescence, apoptosis, and the regulation of mitochondrial activities. Two prohibitin homologues, Phb1 and Phb2, assemble into a high molecular weight complex of approximately 1.2 MDa in the mitochondrial inner membrane, but a nuclear localization of Phb1 and Phb2 also has been reported. Here, we have analyzed the biogenesis and structure of the prohibitin complex in Saccharomyces cerevisiae. Both Phb1 and Phb2 subunits are targeted to mitochondria by unconventional noncleavable targeting sequences at their amino terminal end. Membrane insertion involves binding of newly imported Phb1 to Tim8/13 complexes in the intermembrane space and is mediated by the TIM23-translocase. Assembly occurs via intermediate-sized complexes of approximately 120 kDa containing both Phb1 and Phb2. Conserved carboxy-terminal coiled-coil regions in both subunits mediate the formation of large assemblies in the inner membrane. Single particle electron microscopy of purified prohibitin complexes identifies diverse ring-shaped structures with outer dimensions of approximately 270 x 200 angstroms. Implications of these findings for proposed cellular activities of prohibitins are discussed.

Pubmed ID: 15525670 RIS Download

Mesh terms: Amino Acid Sequence | Cell Cycle | Cell Nucleus | Cloning, Molecular | Electrophoresis, Polyacrylamide Gel | Kinetics | Membrane Transport Proteins | Microscopy, Electron | Mitochondria | Models, Genetic | Molecular Sequence Data | Protein Binding | Protein Structure, Tertiary | Repressor Proteins | Saccharomyces cerevisiae | Saccharomyces cerevisiae Proteins | Time Factors

Research resources used in this publication

None found

Research tools detected in this publication

None found

Data used in this publication

None found

Associated grants


Publication data is provided by the National Library of Medicine ® and PubMed ®. Data is retrieved from PubMed ® on a weekly schedule. For terms and conditions see the National Library of Medicine Terms and Conditions.

We have not found any resources mentioned in this publication.