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Evolutionary conservation of physical and functional interactions between phospholipase D and actin
David J Kusner1, James A Barton, Chunbo Qin
1Department of Internal Medicine, University of Iowa Carrer College of Medicine and VA Medical Center, Iowa City, IA 52242, USA. david-kusner@uiowa.edu
Archives of Biochemistry and Biophysics
|April 2, 2003
Summary
Phospholipase D (PLD) interactions with actin are conserved across species. Both bacterial and plant PLDs bind actin, with polymerization-dependent functional effects similar to human PLD1.
Area of Science:
- Biochemistry
- Molecular Biology
- Evolutionary Biology
Background:
- Phospholipase D (PLD) enzymes share conserved structures and catalytic mechanisms across diverse species.
- The evolutionary conservation of protein-protein interactions for PLDs, particularly with actin, remains largely unexplored.
Purpose of the Study:
- To investigate the evolutionary conservation of physical and functional interactions between mammalian Phospholipase D (PLD) and actin.
- To determine if these interactions extend to bacterial and plant PLD family members.
Main Methods:
- Purification of bacterial and plant PLDs.
- Cosedimentation assays with purified mammalian skeletal muscle alpha-actin.
- Analysis of actin binding affinities (dissociation constants) for bacterial PLD.
- Enzyme activity assays to assess the effects of actin polymerization states (G-actin vs. F-actin) on PLD activity.
Main Results:
- Bacterial and plant PLDs directly interact with F-actin, as evidenced by cosedimentation.
- Bacterial PLD exhibits dual-affinity binding states to G-actin.
- Actin's effect on PLD activity is polymerization-dependent: G-actin inhibits, while F-actin enhances activity.
- Actin modulation of bacterial and plant PLDs shows conserved kinetic properties, efficacies, and potencies comparable to human PLD1.
Conclusions:
- Physical and functional interactions between Phospholipase D (PLD) and actin are highly conserved throughout evolution, from bacteria to mammals.
- These conserved interactions suggest a fundamental biological role for the PLD-actin complex across different life forms.