Faculty Opinions recommendation of Tim50 is a subunit of the TIM23 complex that links protein translocation across the outer and inner mitochondrial membranes.

2002 ◽  
Author(s):  
David Andrews
Keyword(s):  
Protein Translocation ◽  
Mitochondrial Membranes ◽  
A Subunit

scholarly journals Tim50 Is a Subunit of the TIM23 Complex that Links Protein Translocation across the Outer and Inner Mitochondrial Membranes

Cell ◽  
2002 ◽  
Vol 111 (4) ◽  
pp. 519-528 ◽  
Author(s):  
Hayashi Yamamoto ◽  
Masatoshi Esaki ◽  
Takashi Kanamori ◽  
Yasushi Tamura ◽  
Shuh-ichi Nishikawa ◽  
...  
Keyword(s):  
Protein Translocation ◽  
Mitochondrial Membranes ◽  
A Subunit

scholarly journals Archaeal and Bacterial SecD and SecF Homologs Exhibit Striking Structural and Functional Conservation

2006 ◽  
Vol 188 (4) ◽  
pp. 1251-1259 ◽  
Author(s):  
Nicholas J. Hand ◽  
Reinhard Klein ◽  
Anke Laskewitz ◽  
Mechthild Pohlschröder
Keyword(s):  
Protein Translocation ◽  
Specific Protein ◽  
Cold Sensitivity ◽  
Secretory Proteins ◽  
E Coli ◽  
Functional Conservation ◽  
Membrane Complex ◽  
Hydrophobic Membranes ◽  
A Subunit ◽  
Native Host

ABSTRACT The majority of secretory proteins are translocated into and across hydrophobic membranes via the universally conserved Sec pore. Accessory proteins, including the SecDF-YajC Escherichia coli membrane complex, are required for efficient protein secretion. E. coli SecDF-YajC has been proposed to be involved in the membrane cycling of SecA, the cytoplasmic bacterial translocation ATPase, and in the stabilizing of SecG, a subunit of the Sec pore. While there are no identified archaeal homologs of either SecA or SecG, many archaea possess homologs of SecD and SecF. Here, we present the first study that addresses the function of archaeal SecD and SecF homologs. We show that the SecD and SecF components in the model archaeon Haloferax volcanii form a cytoplasmic membrane complex in the native host. Furthermore, as in E. coli, an H. volcanii ΔsecFD mutant strain exhibits both severe cold sensitivity and a Sec-specific protein translocation defect. Taken together, these results demonstrate significant functional conservation among the prokaryotic SecD and SecF homologs despite the distinct composition of their translocation machineries.

scholarly journals Protein import into mitochondria: ATP-dependent protein translocation activity in a submitochondrial fraction enriched in membrane contact sites and specific proteins.

1989 ◽  
Vol 109 (6) ◽  
pp. 2603-2616 ◽  
Author(s):  
L Pon ◽  
T Moll ◽  
D Vestweber ◽  
B Marshallsay ◽  
G Schatz
Keyword(s):  
Protein Import ◽  
Protein Translocation ◽  
Buoyant Density ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Mitochondrial Membranes ◽  
Outer Membranes ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Dependent Protein

To identify the membrane regions through which yeast mitochondria import proteins from the cytoplasm, we have tagged these regions with two different partly translocated precursor proteins. One of these was bound to the mitochondrial surface of ATP-depleted mitochondria and could subsequently be chased into mitochondria upon addition of ATP. The other intermediate was irreversibly stuck across both mitochondrial membranes at protein import sites. Upon subfraction of the mitochondria, both intermediates cofractionated with membrane vesicles whose buoyant density was between that of inner and outer membranes. When these vesicles were prepared from mitochondria containing the chaseable intermediate, they internalized it upon addition of ATP. A non-hydrolyzable ATP analogue was inactive. This vesicle fraction contained closed, right-side-out inner membrane vesicles attached to leaky outer membrane vesicles. The vesicles contained the mitochondrial binding sites for cytoplasmic ribosomes and contained several mitochondrial proteins that were enriched relative to markers of inner or outer membranes. By immunoelectron microscopy, two of these proteins were concentrated at sites where mitochondrial inner and outer membranes are closely apposed. We conclude that these vesicles contain contact sites between the two mitochondrial membranes, that these sites are the entry point for proteins into mitochondria, and that the isolated vesicles are still translocation competent.

scholarly journals Protein translocation across mitochondrial membranes: What a long, strange trip it is

Cell ◽  
1995 ◽  
Vol 83 (4) ◽  
pp. 517-519 ◽  
Author(s):  
Kathleen R. Ryan ◽  
Robert E. Jensen
Keyword(s):  
Protein Translocation ◽  
Mitochondrial Membranes

scholarly journals Key steps in unconventional secretion of fibroblast growth factor 2 reconstituted with purified components

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Julia P Steringer ◽  
Sascha Lange ◽  
Sabína Čujová ◽  
Radek Šachl ◽  
Chetan Poojari ◽  
...  
Keyword(s):  
Secretory Pathway ◽  
Protein Translocation ◽  
Membrane Translocation ◽  
Unconventional Secretion ◽  
Molecular Machinery ◽  
A Subunit ◽  
Heparan Sulfates ◽  
Dynamics Simulations ◽  
Key Steps ◽  
Inside Out

FGF2 is secreted from cells by an unconventional secretory pathway. This process is mediated by direct translocation across the plasma membrane. Here, we define the minimal molecular machinery required for FGF2 membrane translocation in a fully reconstituted inside-out vesicle system. FGF2 membrane translocation is thermodynamically driven by PI(4,5)P2-induced membrane insertion of FGF2 oligomers. The latter serve as dynamic translocation intermediates of FGF2 with a subunit number in the range of 8-12 FGF2 molecules. Vectorial translocation of FGF2 across the membrane is governed by sequential and mutually exclusive interactions with PI(4,5)P2 and heparan sulfates on opposing sides of the membrane. Based on atomistic molecular dynamics simulations, we propose a mechanism that drives PI(4,5)P2 dependent oligomerization of FGF2. Our combined findings establish a novel type of self-sustained protein translocation across membranes revealing the molecular basis of the unconventional secretory pathway of FGF2.

scholarly journals Role of Tim50 in the Transfer of Precursor Proteins from the Outer to the Inner Membrane of Mitochondria

2009 ◽  
Vol 20 (5) ◽  
pp. 1400-1407 ◽  
Author(s):  
Dejana Mokranjac ◽  
Martin Sichting ◽  
Dušan Popov-Čeleketić ◽  
Koyeli Mapa ◽  
Lada Gevorkyan-Airapetov ◽  
...  
Keyword(s):  
Intermembrane Space ◽  
Concerted Action ◽  
Mitochondrial Membranes ◽  
Inner Membrane ◽  
Close Proximity ◽  
Precursor Proteins ◽  
The Matrix ◽  
A Subunit ◽  
Efficient Transfer

Transport of essentially all matrix and a number of inner membrane proteins is governed, entirely or in part, by N-terminal presequences and requires a coordinated action of the translocases of outer and inner mitochondrial membranes (TOM and TIM23 complexes). Here, we have analyzed Tim50, a subunit of the TIM23 complex that is implicated in transfer of precursors from TOM to TIM23. Tim50 is recruited to the TIM23 complex via Tim23 in an interaction that is essentially independent of the rest of the translocase. We find Tim50 in close proximity to the intermembrane space side of the TOM complex where it recognizes both types of TIM23 substrates, those that are to be transported into the matrix and those destined to the inner membrane, suggesting that Tim50 recognizes presequences. This function of Tim50 depends on its association with TIM23. We conclude that the efficient transfer of precursors between TOM and TIM23 complexes requires the concerted action of Tim50 with Tim23.

scholarly journals Protein translocation across mitochondrial membranes

BioEssays ◽  
1992 ◽  
Vol 14 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Ulla Wienhues ◽  
Walter Neupert
Keyword(s):  
Protein Translocation ◽  
Mitochondrial Membranes

Sec61beta, a subunit of the protein translocation channel, is required during Drosophila development

1999 ◽  
Vol 112 (23) ◽  
pp. 4389-4396 ◽  
Author(s):  
R. Valcarcel ◽  
U. Weber ◽  
D.B. Jackson ◽  
V. Benes ◽  
W. Ansorge ◽  
...  
Keyword(s):  
Protein Translocation ◽  
Germ Line ◽  
Follicle Cells ◽  
Gene Encoding ◽  
Homozygous Mutant ◽  
Complex Development ◽  
A Subunit ◽  
Cuticle Proteins ◽  
Higher Eukaryotes

We have identified and isolated mutations in the first Drosophila gene encoding a subunit of the Sec61 protein translocation channel, DSec61beta. While neither the Saccharomyces cerevisiae Sec61beta nor its functional Escherichia coli homologue are essential for viability or for protein translocation, we show that DSec61beta is essential for embryonic development. Homozygous mutant embryos die at the end of embryogenesis and are impaired in the secretion of cuticle proteins from the epidermis. DSec61beta germ line clones, result in defects in dorso-ventral patterning of the egg and are consistent with affected secretion of the protein Gurken from the oocyte to the follicle cells. Clonal analyses in the imaginal discs reveal defects in adult structures, including rhabdomere morphogenesis and a reduction of the size of tarsal segments in the leg. This is the first in vivo study of a component of the protein translocation machinery in higher eukaryotes, and illustrates how a protein that has an inessential, kinetic function in single-cell organisms can become critical for the complex development of a multicellular organism.

Sign in / Sign up

Export Citation Format

Share Document