scholarly journals Compartmentation of cellular activities

2007 ◽  
Vol 28 (2) ◽  
pp. 64
Author(s):  
Trevor Lithgow
Keyword(s):  
Protein Transport ◽  
Yeast Cells ◽  
Yeast Genome ◽  
Intermembrane Space ◽  
Yeast Saccharomyces Cerevisiae ◽  
Technological Advances ◽  
The Matrix ◽  
Cellular Compartments ◽  
New Applications ◽  
Yeast Mutants

In the yeast Saccharomyces cerevisiae, almost one third of cellular function is concerned with maintaining the compartmentation of cellular activities. From classic studies in yeast genetics we have come to understand a great deal of the processes driving the delivery of proteins into these compartments and the metabolic advantages that this provides. With the publication of the yeast genome sequence, ?-omics? level studies began to provide further detail on the compartmentation of yeast cells. Very recent technological advances, including new applications in mass spectrometry, NMR, cryo-electron microscopy and the use of live-cell imaging have also been applied to yeast, because of the comparative analyses that can be done on yeast mutants. The mitochondrion is a complex compartment, carrying more than a thousand proteins that must be transported into and then distributed between, four sub-mitochondrial compartments. Essential molecular machinery in the outer and inner membranes, the intermembrane space and the matrix of mitochondria, drive protein transport, sorting and assembly. A glimpse of how S. cerevisiae and other microbes have provided understanding of cellular compartments is the aim of this review.

Mutations in a 19-amino-acid hydrophobic region of the yeast cytochrome c1 presequence prevent sorting to the mitochondrial intermembrane space

1992 ◽  
Vol 12 (10) ◽  
pp. 4677-4686
Author(s):  
R E Jensen ◽  
S Schmidt ◽  
R J Mark
Keyword(s):  
Amino Acid ◽  
Intermediate Form ◽  
Intermembrane Space ◽  
Protein Amino Acid ◽  
Hydrophobic Region ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cytochrome C1 ◽  
The Matrix ◽  
Hydrophobic Amino Acids ◽  
Mitochondrial Intermembrane Space

Most mitochondrial proteins destined for the intermembrane space (IMS) carry in their presequence information for localization to the IMS in addition to information for their import. By selecting for mutants in the yeast Saccharomyces cerevisiae that mislocalize an IMS-targeted fusion protein, we identified mutations in the IMS sorting signal of the cytochrome c1 protein. Amino acid substitutions or deletions in a stretch of 19 hydrophobic amino acids of the cytochrome c1 presequence resulted in accumulation of the intermediate form of the cytochrome c1 protein in the matrix. In some cases, the accumulated intermediate appeared to be slowly exported from the matrix, across the inner membrane to the IMS. Our results support the hypothesis that the cytochrome c1 precursor is normally imported completely into the matrix and then exported to the IMS.

scholarly journals Two Saccharomyces cerevisiae genes which control sensitivity to G1 arrest induced by Kluyveromyces lactis toxin.

1994 ◽  
Vol 14 (9) ◽  
pp. 6306-6316 ◽  
Author(s):  
A R Butler ◽  
J H White ◽  
Y Folawiyo ◽  
A Edlin ◽  
D Gardiner ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Copy Number ◽  
Kluyveromyces Lactis ◽  
Yeast Cells ◽  
Yeast Genome ◽  
G1 Arrest ◽  
Yeast Saccharomyces Cerevisiae ◽  
Toxin Resistance ◽  
Complementation Groups ◽  
Diploid Cells

The Kluyveromyces lactis toxin causes an arrest of sensitive yeast cells in the G1 phase of the cell division cycle. Two complementary genetic approaches have been undertaken in the yeast Saccharomyces cerevisiae to understand the mode of action of this toxin. First, two sequences conferring toxin resistance specifically in high copy number have been isolated and shown to encode a tRNA(Glu3) and a novel polypeptide. Disruption of the latter sequence in the yeast genome conferred toxin resistance and revealed that it was nonessential, while the effect of the tRNA(Glu)3 was highly specific and mediated resistance by affecting the toxin's target. An alpha-specific, copy number-independent suppressor of toxin sensitivity was also isolated and identified as MATa, consistent with the observation that diploid cells are partially resistant to the toxin. Second, in a comprehensive screen for toxin-resistant mutants, representatives of 13 complementation groups have been obtained and characterized to determine whether they are altered in the toxin's intracellular target. Of 10 genes found to affect the target process, one (KTI12) was found to encode the novel polypeptide previously identified as a multicopy resistance determinant. Thus, both loss of KTI12 function and elevated KTI12 copy number can cause resistance to the K. lactis toxin.

Mechanisms and physiological impact of the dual localization of mitochondrial intermembrane space proteins

2014 ◽  
Vol 42 (4) ◽  
pp. 952-958 ◽  
Author(s):  
Carmelina Petrungaro ◽  
Jan Riemer
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Function ◽  
The Other ◽  
Yeast Cells ◽  
Eukaryotic Cells ◽  
Intermembrane Space ◽  
Dual Localization ◽  
Mitochondrial Intermembrane Space ◽  
Physiological Impact ◽  
Cellular Compartments

Eukaryotic cells developed diverse mechanisms to guide proteins to more than one destination within the cell. Recently, the proteome of the IMS (intermembrane space) of mitochondria of yeast cells was identified showing that approximately 20% of all soluble IMS proteins are dually localized to the IMS, as well as to other cellular compartments. Half of these dually localized proteins are important for oxidative stress defence and the other half are involved in energy homoeostasis. In the present review, we discuss the mechanisms leading to the dual localization of IMS proteins and the implications for mitochondrial function.

Transpositional competence and transcription of endogenous Ty elements in Saccharomyces cerevisiae: implications for regulation of transposition

1988 ◽  
Vol 8 (9) ◽  
pp. 3571-3581 ◽  
Author(s):  
M J Curcio ◽  
N J Sanders ◽  
D J Garfinkel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Target Genes ◽  
Yeast Cells ◽  
Yeast Genome ◽  
Yeast Saccharomyces Cerevisiae ◽  
Transposition Frequency ◽  
Ty Elements ◽  
Gal1 Promoter ◽  
Per Gene ◽  
Posttranscriptional Level

Transposition of Ty elements in the yeast Saccharomyces cerevisiae occurs through an RNA intermediate. Although Ty RNA accounts for 5 to 10% of the total polyadenylated RNA in a haploid cell, the transposition frequency is only 10(-7) to 10(-8) per gene. To determine whether Ty elements native to the yeast genome are transpositionally competent, two elements were fused to the GAL1 promoter and tested for their ability to transpose. These native elements, Ty1-588 and Ty2-117, transposed at high levels when the GAL1 promoter was induced. Three Ty's identified as spontaneous transpositions in specific target genes were also tested. Of these three, Ty2-917 and the previously characterized element Ty1-H3 were shown to be transpositionally competent. The third element, Ty1-H1, was transposition defective. In addition, we marked the chromosomal copy of Ty1-588 with the NEO gene and demonstrated that Ty1-588NEO was actively transcribed in yeast cells. Ty1-588NEO transcription was regulated by the SPT3 and MAT loci in the same manner as that observed for Ty's collectively. These results indicate that the yeast genome contains functional Ty elements. The presence of a transpositionally competent, actively transcribed element suggests that regulation of Ty transposition occurs at a posttranscriptional level.

scholarly journals A Genetics Laboratory Module Involving Selection and Identification of Lysine Synthesis Mutants in the Yeast Saccharomyces cerevisiae

2000 ◽  
Vol 1 (1) ◽  
pp. 26-30
Author(s):  
JILL B. KEENEY ◽  
RUTH REED
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Spontaneous Mutation ◽  
Selective Medium ◽  
Lysine Biosynthesis ◽  
Yeast Cells ◽  
Yeast Genome ◽  
Yeast Saccharomyces Cerevisiae ◽  
Laboratory Exercise ◽  
College Sophomores ◽  
Mutant Genes

We have developed a laboratory exercise, currently being used with college sophomores, which uses the yeast Saccharomyces cerevisiae to convey the concepts of amino acid biosynthesis, mutation, and gene complementation. In brief, selective medium is used to isolate yeast cells carrying a mutation in the lysine biosynthesis pathway. A spontaneous mutation in any one of three separate genetic loci will allow for growth on selective media; however, the frequency of mutations isolated from each locus differs. Following isolation of a mutated strain, students use complementation analysis to identify which gene contains the mutation. Since the yeast genome has been mapped and sequenced, students with access to the Internet can then research and develop hypotheses to explain the differences in frequencies of mutant genes obtained.

scholarly journals Two Saccharomyces cerevisiae genes which control sensitivity to G1 arrest induced by Kluyveromyces lactis toxin

1994 ◽  
Vol 14 (9) ◽  
pp. 6306-6316
Author(s):  
A R Butler ◽  
J H White ◽  
Y Folawiyo ◽  
A Edlin ◽  
D Gardiner ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Copy Number ◽  
Kluyveromyces Lactis ◽  
Yeast Cells ◽  
Yeast Genome ◽  
G1 Arrest ◽  
Yeast Saccharomyces Cerevisiae ◽  
Toxin Resistance ◽  
Complementation Groups ◽  
Diploid Cells

The Kluyveromyces lactis toxin causes an arrest of sensitive yeast cells in the G1 phase of the cell division cycle. Two complementary genetic approaches have been undertaken in the yeast Saccharomyces cerevisiae to understand the mode of action of this toxin. First, two sequences conferring toxin resistance specifically in high copy number have been isolated and shown to encode a tRNA(Glu3) and a novel polypeptide. Disruption of the latter sequence in the yeast genome conferred toxin resistance and revealed that it was nonessential, while the effect of the tRNA(Glu)3 was highly specific and mediated resistance by affecting the toxin's target. An alpha-specific, copy number-independent suppressor of toxin sensitivity was also isolated and identified as MATa, consistent with the observation that diploid cells are partially resistant to the toxin. Second, in a comprehensive screen for toxin-resistant mutants, representatives of 13 complementation groups have been obtained and characterized to determine whether they are altered in the toxin's intracellular target. Of 10 genes found to affect the target process, one (KTI12) was found to encode the novel polypeptide previously identified as a multicopy resistance determinant. Thus, both loss of KTI12 function and elevated KTI12 copy number can cause resistance to the K. lactis toxin.

scholarly journals Mutations in a 19-amino-acid hydrophobic region of the yeast cytochrome c1 presequence prevent sorting to the mitochondrial intermembrane space.

1992 ◽  
Vol 12 (10) ◽  
pp. 4677-4686 ◽  
Author(s):  
R E Jensen ◽  
S Schmidt ◽  
R J Mark
Keyword(s):  
Amino Acid ◽  
Intermediate Form ◽  
Intermembrane Space ◽  
Protein Amino Acid ◽  
Hydrophobic Region ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cytochrome C1 ◽  
The Matrix ◽  
Hydrophobic Amino Acids ◽  
Mitochondrial Intermembrane Space

Most mitochondrial proteins destined for the intermembrane space (IMS) carry in their presequence information for localization to the IMS in addition to information for their import. By selecting for mutants in the yeast Saccharomyces cerevisiae that mislocalize an IMS-targeted fusion protein, we identified mutations in the IMS sorting signal of the cytochrome c1 protein. Amino acid substitutions or deletions in a stretch of 19 hydrophobic amino acids of the cytochrome c1 presequence resulted in accumulation of the intermediate form of the cytochrome c1 protein in the matrix. In some cases, the accumulated intermediate appeared to be slowly exported from the matrix, across the inner membrane to the IMS. Our results support the hypothesis that the cytochrome c1 precursor is normally imported completely into the matrix and then exported to the IMS.

scholarly journals Transpositional competence and transcription of endogenous Ty elements in Saccharomyces cerevisiae: implications for regulation of transposition.

1988 ◽  
Vol 8 (9) ◽  
pp. 3571-3581 ◽  
Author(s):  
M J Curcio ◽  
N J Sanders ◽  
D J Garfinkel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Target Genes ◽  
Yeast Cells ◽  
Yeast Genome ◽  
Yeast Saccharomyces Cerevisiae ◽  
Transposition Frequency ◽  
Ty Elements ◽  
Gal1 Promoter ◽  
Per Gene ◽  
Posttranscriptional Level

Transposition of Ty elements in the yeast Saccharomyces cerevisiae occurs through an RNA intermediate. Although Ty RNA accounts for 5 to 10% of the total polyadenylated RNA in a haploid cell, the transposition frequency is only 10(-7) to 10(-8) per gene. To determine whether Ty elements native to the yeast genome are transpositionally competent, two elements were fused to the GAL1 promoter and tested for their ability to transpose. These native elements, Ty1-588 and Ty2-117, transposed at high levels when the GAL1 promoter was induced. Three Ty's identified as spontaneous transpositions in specific target genes were also tested. Of these three, Ty2-917 and the previously characterized element Ty1-H3 were shown to be transpositionally competent. The third element, Ty1-H1, was transposition defective. In addition, we marked the chromosomal copy of Ty1-588 with the NEO gene and demonstrated that Ty1-588NEO was actively transcribed in yeast cells. Ty1-588NEO transcription was regulated by the SPT3 and MAT loci in the same manner as that observed for Ty's collectively. These results indicate that the yeast genome contains functional Ty elements. The presence of a transpositionally competent, actively transcribed element suggests that regulation of Ty transposition occurs at a posttranscriptional level.

scholarly journals Mapping protein interactions in the active TOM-TIM23 supercomplex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ridhima Gomkale ◽  
Andreas Linden ◽  
Piotr Neumann ◽  
Alexander Benjamin Schendzielorz ◽  
Stefan Stoldt ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Matrix Protein ◽  
Protein Transport ◽  
Mitochondrial Proteins ◽  
Cross Linking ◽  
Intermembrane Space ◽  
Precursor Proteins ◽  
The Matrix ◽  
Targeting Signals ◽  
Chemical Cross Linking

AbstractNuclear-encoded mitochondrial proteins destined for the matrix have to be transported across two membranes. The TOM and TIM23 complexes facilitate the transport of precursor proteins with N-terminal targeting signals into the matrix. During transport, precursors are recognized by the TIM23 complex in the inner membrane for handover from the TOM complex. However, we have little knowledge on the organization of the TOM-TIM23 transition zone and on how precursor transfer between the translocases occurs. Here, we have designed a precursor protein that is stalled during matrix transport in a TOM-TIM23-spanning manner and enables purification of the translocation intermediate. Combining chemical cross-linking with mass spectrometric analyses and structural modeling allows us to map the molecular environment of the intermembrane space interface of TOM and TIM23 as well as the import motor interactions with amino acid resolution. Our analyses provide a framework for understanding presequence handover and translocation during matrix protein transport.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

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