Mitochondria are dynamic organelles that continuously undergo fission and fusion. These dynamic events regulate the size and shape of mitochondria and play critical roles in cell physiology, as fission and fusion proteins have been implicated in the regulation of apoptosis and mutations in human fusion proteins have been linked to neurodegenerative diseases. In the yeast S. cerevisiae, at least three proteins are essential for mitochondrial fission: Dnm1, Mdv1, and Fis1 Interestingly, orthologs of two of these proteins exist in mammalian cells indicating that the molecular processes underlying mitochondrial fission are well conserved. Recent studies in yeast suggest the dynamin related GTPase Dnm1 drives membrane constriction during fission by self-assembly and conformational changes, and that these alterations in Dnm1 structure may be regulated by Mdv1 and Fis1. To understand in mechanistic detail how Dnm1, Mdv1, and Fis1 assemble into a fission competent machine and, once the machine is constructed, how the proteins function together to mediate the constriction and ultimate division of mitochondria, mitochondrial fission events will be reconstituted in vitro. This will include hydrodynamic analysis of purified proteins, Dnm1 assembly and GTPase assays in the presence of Mdv1 and Fis1, and the reconstitution of the fission machine on lipid bi- layers. These studies will define the minimal fission machine and will determine the roles of each fission protein and of nucleotide binding and hvdrolysis bv Dnm1 in fission. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32GM078749-01
Application #
7156519
Study Section
Special Emphasis Panel (ZRG1-F05-J (20))
Program Officer
Rodewald, Richard D
Project Start
2006-12-01
Project End
2009-05-31
Budget Start
2006-12-01
Budget End
2007-11-30
Support Year
1
Fiscal Year
2006
Total Cost
$45,976
Indirect Cost
Name
University of California Davis
Department
Anatomy/Cell Biology
Type
Schools of Arts and Sciences
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
Mears, Jason A; Lackner, Laura L; Fang, Shunming et al. (2011) Conformational changes in Dnm1 support a contractile mechanism for mitochondrial fission. Nat Struct Mol Biol 18:20-6
DeVay, Rachel M; Dominguez-Ramirez, Lenin; Lackner, Laura L et al. (2009) Coassembly of Mgm1 isoforms requires cardiolipin and mediates mitochondrial inner membrane fusion. J Cell Biol 186:793-803
Lackner, Laura L; Horner, Jennifer S; Nunnari, Jodi (2009) Mechanistic analysis of a dynamin effector. Science 325:874-7
Lackner, Laura L; Nunnari, Jodi M (2009) The molecular mechanism and cellular functions of mitochondrial division. Biochim Biophys Acta 1792:1138-44
Lee, Young Jin; Lackner, Laura L; Nunnari, Jodi M et al. (2007) Shotgun cross-linking analysis for studying quaternary and tertiary protein structures. J Proteome Res 6:3908-17