scholarly journals Dnm1p Gtpase-Mediated Mitochondrial Fission Is a Multi-Step Process Requiring the Novel Integral Membrane Component Fis1p

2000 ◽  
Vol 151 (2) ◽  
pp. 367-380 ◽  
Author(s):  
A.D. Mozdy ◽  
J.M. McCaffery ◽  
J.M. Shaw
Keyword(s):  
Membrane Protein ◽  
Mitochondrial Membrane ◽  
Mitochondrial Fission ◽  
First Integral ◽  
Integral Membrane Protein ◽  
Morphological Evidence ◽  
Outer Mitochondrial Membrane ◽  
Step Process ◽  
Membrane Recruitment ◽  
New Genes

Yeast Dnm1p is a soluble, dynamin-related GTPase that assembles on the outer mitochondrial membrane at sites where organelle division occurs. Although these Dnm1p-containing complexes are thought to trigger constriction and fission, little is known about their composition and assembly, and molecules required for their membrane recruitment have not been isolated. Using a genetic approach, we identified two new genes in the fission pathway, FIS1 and FIS2. FIS1 encodes a novel, outer mitochondrial membrane protein with its amino terminus exposed to the cytoplasm. Fis1p is the first integral membrane protein shown to participate in a eukaryotic membrane fission event. In a related study (Tieu, Q., and J. Nunnari. 2000. J. Cell Biol. 151:353–365), it was shown that the FIS2 gene product (called Mdv1p) colocalizes with Dnm1p on mitochondria. Genetic and morphological evidence indicate that Fis1p, but not Mdv1p, function is required for the proper assembly and distribution of Dnm1p-containing fission complexes on mitochondrial tubules. We propose that mitochondrial fission in yeast is a multi-step process, and that membrane-bound Fis1p is required for the proper assembly, membrane distribution, and function of Dnm1p-containing complexes during fission.

scholarly journals A novel motif in the yeast mitochondrial dynamin Dnm1 is essential for adaptor binding and membrane recruitment

2012 ◽  
Vol 199 (4) ◽  
pp. 613-622 ◽  
Author(s):  
Huyen T. Bui ◽  
Mary A. Karren ◽  
Debjani Bhar ◽  
Janet M. Shaw
Keyword(s):  
Mitochondrial Membrane ◽  
Mitochondrial Fission ◽  
Adaptor Proteins ◽  
Structural Features ◽  
Outer Mitochondrial Membrane ◽  
Membrane Recruitment ◽  
Suppressor Mutations ◽  
Guanosine Triphosphatase ◽  
Related Proteins ◽  
Binding Interfaces

To initiate mitochondrial fission, dynamin-related proteins (DRPs) must bind specific adaptors on the outer mitochondrial membrane. The structural features underlying this interaction are poorly understood. Using yeast as a model, we show that the Insert B domain of the Dnm1 guanosine triphosphatase (a DRP) contains a novel motif required for association with the mitochondrial adaptor Mdv1. Mutation of this conserved motif specifically disrupted Dnm1–Mdv1 interactions, blocking Dnm1 recruitment and mitochondrial fission. Suppressor mutations in Mdv1 that restored Dnm1–Mdv1 interactions and fission identified potential protein-binding interfaces on the Mdv1 β-propeller domain. These results define the first known function for Insert B in DRP–adaptor interactions. Based on the variability of Insert B sequences and adaptor proteins, we propose that Insert B domains and mitochondrial adaptors have coevolved to meet the unique requirements for mitochondrial fission of different organisms.

scholarly journals Possibility of Cytoplasmic pre-tRNA Splicing: the Yeast tRNA Splicing Endonuclease Mainly Localizes on the Mitochondria

2003 ◽  
Vol 14 (8) ◽  
pp. 3266-3279 ◽  
Author(s):  
Tohru Yoshihisa ◽  
Kaori Yunoki-Esaki ◽  
Chie Ohshima ◽  
Nobuyuki Tanaka ◽  
Toshiya Endo
Keyword(s):  
Membrane Protein ◽  
Mitochondrial Membrane ◽  
Integral Membrane Protein ◽  
Outer Mitochondrial Membrane ◽  
Endonuclease Activity ◽  
Mitochondrial Localization ◽  
Mutant Proteins ◽  
Trna Splicing ◽  
Yeast Trna ◽  
Mutant Cells

Pre-tRNA splicing has been believed to occur in the nucleus. In yeast, the tRNA splicing endonuclease that cleaves the exon-intron junctions of pre-tRNAs consists of Sen54p, Sen2p, Sen34p, and Sen15p and was thought to be an integral membrane protein of the inner nuclear envelope. Here we show that the majority of Sen2p, Sen54p, and the endonuclease activity are not localized in the nucleus, but on the mitochondrial surface. The endonuclease is peripherally associated with the cytosolic surface of the outer mitochondrial membrane. A Sen54p derivative artificially fixed on the mitochondria as an integral membrane protein can functionally replace the authentic Sen54p, whereas mutant proteins defective in mitochondrial localization are not fully active. sen2 mutant cells accumulate unspliced pre-tRNAs in the cytosol under the restrictive conditions, and this export of the pre-tRNAs partly depends on Los1p, yeast exportin-t. It is difficult to explain these results from the view of tRNA splicing in the nucleus. We rather propose a new possibility that tRNA splicing occurs on the mitochondrial surface in yeast.

scholarly journals Constriction and Dnm1p Recruitment Are Distinct Processes in Mitochondrial Fission

2003 ◽  
Vol 14 (5) ◽  
pp. 1953-1963 ◽  
Author(s):  
Aster Legesse-Miller ◽  
Ramiro H. Massol ◽  
Tom Kirchhausen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fluorescence Imaging ◽  
Hot Spots ◽  
Mitochondrial Membrane ◽  
Mitochondrial Fission ◽  
Three Dimensional ◽  
Time Lapse ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Matrix ◽  
Different Shapes

Mitochondria undergo cycles of fusion and fission crucial for organelle homeostasis. Fission is regulated partially by recruitment of the large GTPase Dnm1p to the outer mitochondrial membrane. Using three-dimensional time-lapse fluorescence imaging of Saccharomyces cerevisiae cells, we found that Dnm1p-EGFP appears and disappears at “hot spots” along mitochondrial tubes. It forms patches that convert rapidly into different shapes regardless of whether mitochondrial fission ensues or not. Moreover, the thickness of the mitochondrial matrix displays frequent temporal fluctuations apparently unrelated to fission or to recruitment of Dnm1p-EGFP. These results suggest that mitochondrial fission requires coordination of at least two distinct processes.

scholarly journals Genetic analysis of dTSPO , an outer mitochondrial membrane protein, reveals its functions in apoptosis, longevity, and Aβ42‐induced neurodegeneration

Aging Cell ◽  
2014 ◽  
Vol 13 (3) ◽  
pp. 507-518 ◽  
Author(s):  
Ran Lin ◽  
Alessia Angelin ◽  
Federico Da Settimo ◽  
Claudia Martini ◽  
Sabrina Taliani ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Genetic Analysis ◽  
Mitochondrial Membrane ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Membrane Protein

scholarly journals The Outer Mitochondrial Membrane Protein mitoNEET Contains a Novel Redox-active 2Fe-2S Cluster

2007 ◽  
Vol 282 (33) ◽  
pp. 23745-23749 ◽  
Author(s):  
Sandra E. Wiley ◽  
Mark L. Paddock ◽  
Edward C. Abresch ◽  
Larry Gross ◽  
Peter van der Geer ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Mitochondrial Membrane ◽  
Outer Mitochondrial Membrane ◽  
Redox Active ◽  
Mitochondrial Membrane Protein

scholarly journals Expanding the Range of Redox Potentials of the 2Fe-2S Clusters of the Outer Mitochondrial Membrane Protein MitoNEET

2010 ◽  
Vol 98 (3) ◽  
pp. 235a
Author(s):  
John A. Zuris ◽  
Mark L. Paddock ◽  
Andrea R. Conlan ◽  
Edward C. Abresch ◽  
Rachel Nechushtai ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Mitochondrial Membrane ◽  
Outer Mitochondrial Membrane ◽  
Redox Potentials ◽  
Mitochondrial Membrane Protein

scholarly journals Structural Basis for Phosphate Stabilization of the Uniquely Coordinated 2Fe-2S Cluster of the Outer Mitochondrial Membrane Protein MitoNEET.∗

2009 ◽  
Vol 96 (3) ◽  
pp. 442a-443a ◽  
Author(s):  
Christina Homer ◽  
David Yee ◽  
Herbert L. Axelrod ◽  
Aina E. Cohen ◽  
Edward C. Abresch ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Mitochondrial Membrane ◽  
Structural Basis ◽  
Outer Mitochondrial Membrane ◽  
Mitochondrial Membrane Protein
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