Journal article
Allosteric Modulation of Drp1 Mechanoenzyme Assembly and Mitochondrial Fission by the Variable Domain
The Journal of biological chemistry, Vol.287(14), pp.10990-11001
03/30/2012
DOI: 10.1074/jbc.M112.342105
PMCID: PMC3322891
PMID: 22334657
Abstract
Background:
Mechanisms of Drp1-mediated mitochondrial fission are poorly understood.
Results:
Substitution of the Drp1 variable domain causes a spectrum of assembly and activity phenotypes but does not compromise the stalk domain-mediated recruitment of Drp1 to the mitochondrial anchoring protein Mff.
Conclusion:
The variable domain modulates Drp1 activity through oligomeric assembly.
Significance:
Insight into Drp1 regulatory mechanisms is essential for understanding mitochondrial biology.
The mechanoenzyme dynamin-related protein 1 (Drp1) hydrolyzes GTP to power mitochondrial fission, a process required for organelle biogenesis, quality control, transport, and apoptosis. The pleckstrin homology domain of dynamin is essential for targeting to and severing of lipid tubules, but the function of the corresponding variable domain (VD, or insert B) of Drp1 is unknown. We replaced the VD of Drp1 with a panel of linker sequences of varying length and secondary structure composition and found that the VD is dispensable for mitochondrial recruitment, association with the Drp1-anchoring protein Mff (
m
itochondrial
f
ission
f
actor), and basal and protonophore-induced mitochondrial fragmentation. Indeed, several ΔVD mutants constitutively localized to the outer mitochondrial membrane (OMM) and fragmented mitochondria more efficiently than wild-type Drp1. Consistent with an autoinhibitory role of the VD, we identified Arg-376 in the Drp1 stalk domain as necessary for Mff interaction, assembly into spirals, and mitochondrial fission. Switching the length of N- and C-terminal α-helical segments in the VD-replacing linker converted Drp1 from constitutively active and OMM-localized to inactive and cytosolic. Other hypoactive ΔVD mutants formed stable and characteristically shaped aggregates, including extended filaments. Phosphorylation of a PKA site bordering the VD disassembled the filamentous ΔVD mutant and accelerated cytosolic diffusion of full-length Drp1. We propose a model for regulation of Drp1-dependent mitochondrial fission, in which posttranslational modifications in or near the VD alter the conformation of a membrane-proximal oligomerization interface to influence Drp1 assembly rate and/or geometry. This in turn modulates Arg-376-dependent OMM targeting of Drp1 via multivalent interactions with Mff.
Details
- Title: Subtitle
- Allosteric Modulation of Drp1 Mechanoenzyme Assembly and Mitochondrial Fission by the Variable Domain
- Creators
- Stefan Strack - From the Department of Pharmacology, The University of Iowa, Iowa City, Iowa 52242J. Thomas Cribbs - From the Department of Pharmacology, The University of Iowa, Iowa City, Iowa 52242
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.287(14), pp.10990-11001
- DOI
- 10.1074/jbc.M112.342105
- PMID
- 22334657
- PMCID
- PMC3322891
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Publisher
- American Society for Biochemistry and Molecular Biology; 9650 Rockville Pike, Bethesda, MD 20814, U.S.A
- Grant note
- NS043254; NS056244; NS057714 / National Institutes of Health
- Alternative title
- Autoinhibition by the Drp1 Variable Domain
- Language
- English
- Date published
- 03/30/2012
- Academic Unit
- Pathology; Iowa Neuroscience Institute; Neuroscience and Pharmacology; Ophthalmology and Visual Sciences
- Record Identifier
- 9984040580102771
Metrics
29 Record Views