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An intersubunit signaling network coordinates ATP hydrolysis by m-AAA proteases
Steffen Augustin1, Florian Gerdes, Sukyeong Lee
1Institute for Genetics, Center for Molecular Medicine Cologne, University of Cologne, Germany.
Molecular Cell
|September 15, 2009
Summary
Ring-shaped AAA+ ATPases coordinate ATP hydrolysis in mitochondrial m-AAA protease complexes. This coordinated action, not stochastic, is crucial for substrate membrane dislocation, revealing energy conversion mechanisms.
Area of Science:
- Molecular biology
- Biochemistry
- Mitochondrial function
Background:
- AAA+ ATPases are ring-shaped molecular machines crucial for cellular processes.
- Their regulation and coupling of ATP hydrolysis to mechanical work remain poorly understood.
- Mitochondrial inner membrane m-AAA proteases are conserved AAA+ machines.
Purpose of the Study:
- To elucidate the mechanism of coordinated ATP hydrolysis in m-AAA protease ring complexes.
- To identify the signaling pathways regulating ATP hydrolysis within AAA+ rings.
- To understand the coupling of ATPase activity to mechanical work and substrate processing.
Main Methods:
- Demonstration of coordinated ATP hydrolysis in m-AAA protease complexes.
- Utilizing unbiased genetic screens to identify intersubunit signaling components.
- Investigating the role of AAA motifs and pore loops in ATPase regulation.
- Assessing the requirement for coordinated hydrolysis in substrate membrane dislocation and processing.
Main Results:
- ATP binding to one AAA subunit inhibits hydrolysis in neighboring subunits, enforcing coordinated ATP turnover.
- An intersubunit signaling pathway involving conserved AAA motifs and pore loops was defined.
- Coordinated ATP hydrolysis is essential for substrate membrane dislocation.
- Coordinated ATP hydrolysis is not required for substrate processing.
Conclusions:
- AAA+ ring complexes exhibit coordinated, regulated ATP hydrolysis.
- This coordination is mediated by intersubunit signaling and coupled to mechanical work.
- The findings offer insights into energy transduction by AAA+ proteins in cellular processes.
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