scholarly journals Making two organelles from one: Woronin body biogenesis by peroxisomal protein sorting

2008 ◽  
Vol 180 (2) ◽  
pp. 325-339 ◽  
Author(s):  
Fangfang Liu ◽  
Seng Kah Ng ◽  
Yanfen Lu ◽  
Wilson Low ◽  
Julian Lai ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Neurospora Crassa ◽  
Filamentous Fungi ◽  
Dense Core ◽  
Cell Cortex ◽  
Protein Matrix ◽  
Woronin Body ◽  
Membrane Bound ◽  
And Control ◽  
Dual Functions

Woronin bodies (WBs) are dense-core organelles that are found exclusively in filamentous fungi and that seal the septal pore in response to wounding. These organelles consist of a membrane-bound protein matrix comprised of the HEX protein and, although they form from peroxisomes, their biogenesis is poorly understood. In Neurospora crassa, we identify Woronin sorting complex (WSC), a PMP22/MPV17-related membrane protein with dual functions in WB biogenesis. WSC localizes to large peroxisome membranes where it self-assembles into detergent-resistant oligomers that envelop HEX assemblies, producing asymmetrical nascent WBs. In a reaction requiring WSC, these structures are delivered to the cell cortex, which permits partitioning of the nascent WB and WB inheritance. Our findings suggest that WSC and HEX collaborate and control distinct aspects of WB biogenesis and that cortical association depends on WSC, which in turn depends on HEX. This dependency helps order events across the organellar membrane, permitting the peroxisome to produce a second organelle with a distinct composition and intracellular distribution.

scholarly journals Improving cell-free glycoprotein synthesis by characterizing and enriching native membrane vesicles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jasmine M. Hershewe ◽  
Katherine F. Warfel ◽  
Shaelyn M. Iyer ◽  
Justin A. Peruzzi ◽  
Claretta J. Sullivan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Synthetic Biology ◽  
Membrane Protein ◽  
Membrane Vesicles ◽  
Processing Methods ◽  
Glycoprotein Synthesis ◽  
On Demand ◽  
Free Gene ◽  
Membrane Bound

AbstractCell-free gene expression (CFE) systems from crude cellular extracts have attracted much attention for biomanufacturing and synthetic biology. However, activating membrane-dependent functionality of cell-derived vesicles in bacterial CFE systems has been limited. Here, we address this limitation by characterizing native membrane vesicles in Escherichia coli-based CFE extracts and describing methods to enrich vesicles with heterologous, membrane-bound machinery. As a model, we focus on bacterial glycoengineering. We first use multiple, orthogonal techniques to characterize vesicles and show how extract processing methods can be used to increase concentrations of membrane vesicles in CFE systems. Then, we show that extracts enriched in vesicle number also display enhanced concentrations of heterologous membrane protein cargo. Finally, we apply our methods to enrich membrane-bound oligosaccharyltransferases and lipid-linked oligosaccharides for improving cell-free N-linked and O-linked glycoprotein synthesis. We anticipate that these methods will facilitate on-demand glycoprotein production and enable new CFE systems with membrane-associated activities.

The tetraspanin TSP3 of Neurospora crassa is a vacuolar membrane protein and shares characteristics with IDI proteins

Mycologia ◽  
2016 ◽  
Vol 108 (3) ◽  
pp. 581-589
Author(s):  
Daniela Heine ◽  
Linda Petereit ◽  
Marcel R. Schumann ◽  
Diana Patzelt ◽  
Leila Rachid ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Neurospora Crassa ◽  
Vacuolar Membrane

scholarly journals Characterization of the stilbenedisulphonate binding site on band 3 Memphis variant II (Pro-854→Leu)

1996 ◽  
Vol 317 (2) ◽  
pp. 509-514 ◽  
Author(s):  
James M. SALHANY ◽  
Renee L. SLOAN ◽  
Lawrence M. SCHOPFER
Keyword(s):  
Binding Site ◽  
Conformational Changes ◽  
Covalent Binding ◽  
Band 3 ◽  
Blood Group Antigen ◽  
Cross Linking ◽  
Anion Exchange Protein ◽  
Membrane Bound ◽  
And Control

Band 3 Memphis variant II is a mutant anion-exchange protein associated with the Diego a+ blood group antigen. There are two mutations in this transporter: Lys-56 → Glu within the cytoplasmic domain, and Pro-854 → Leu within the membrane-bound domain. The Pro-854 mutation, which is thought to give rise to the antigenicity, is located within the C-terminal subdomain of the membrane-bound domain. Yet, there is an apparent enhancement in the rate of covalent binding of H2DIDS (4,4´-di-isothiocyanatodihydro-2,2´-stilbenedisulphonate) to ‘lysine A’ (Lys-539) in the N-terminal subdomain, suggesting widespread conformational changes. In this report, we have used various kinetic assays which differentiate between conformational changes in the two subdomains, to characterize the stilbenedisulphonate site on band 3 Memphis variant II. We have found a significantly higher H2DIDS (a C-terminal-sensitive inhibitor) affinity for band 3 Memphis variant II, due to a lower H2DIDS ‘off’ rate constant, but no difference was found between mutant and control when DBDS (4,4´-dibenzamido-2,2´-stilbenedisulphonate) (a C-terminal-insensitive inhibitor) ‘off’ rates were measured. Furthermore, there were no differences in the rates of covalent binding to lysine A, for either DIDS (4,4´-di-isothiocyanato-2,2´-stilbenedisulphonate) or H2DIDS. However, the rate of covalent intrasubunit cross-linking of Lys-539 and Lys-851 by H2DIDS was abnormally low for band 3 Memphis variant II. These results suggest that the Pro-854 → Leu mutation causes a localized conformational change in the C-terminal subdomain of band 3.

scholarly journals The ribosome receptors Mrx15 and Mba1 jointly organize cotranslational insertion and protein biogenesis in mitochondria

2018 ◽  
Vol 29 (20) ◽  
pp. 2386-2396 ◽  
Author(s):  
Braulio Vargas Möller-Hergt ◽  
Andreas Carlström ◽  
Katharina Stephan ◽  
Axel Imhof ◽  
Martin Ott
Keyword(s):  
Membrane Protein ◽  
Mitochondrial Gene ◽  
Ribosomal Subunit ◽  
Mitochondrial Translation ◽  
Protein Insertion ◽  
Mitochondrial Ribosomes ◽  
Protein Biogenesis ◽  
Membrane Bound ◽  
Highly Hydrophobic ◽  
Soluble C

Mitochondrial gene expression in Saccharomyces cerevisiae is responsible for the production of highly hydrophobic subunits of the oxidative phosphorylation system. Membrane insertion occurs cotranslationally on membrane-bound mitochondrial ribosomes. Here, by employing a systematic mass spectrometry–based approach, we discovered the previously uncharacterized membrane protein Mrx15 that interacts via a soluble C-terminal domain with the large ribosomal subunit. Mrx15 contacts mitochondrial translation products during their synthesis and plays, together with the ribosome receptor Mba1, an overlapping role in cotranslational protein insertion. Taken together, our data reveal how these ribosome receptors organize membrane protein biogenesis in mitochondria.

scholarly journals Cell Secretion: Current Structural and Biochemical Insights

2010 ◽  
Vol 10 ◽  
pp. 2054-2069 ◽  
Author(s):  
Saurabh Trikha ◽  
Elizabeth C. Lee ◽  
Aleksandar M. Jeremic
Keyword(s):  
Plasma Membrane ◽  
Secretory Vesicles ◽  
Intercellular Signaling ◽  
Cell Secretion ◽  
Membrane Structures ◽  
Calcium Dependent ◽  
Cell Plasma ◽  
Membrane Bound ◽  
And Control ◽  
Fusion Pores

Essential physiological functions in eukaryotic cells, such as release of hormones and digestive enzymes, neurotransmission, and intercellular signaling, are all achieved by cell secretion. In regulated (calcium-dependent) secretion, membrane-bound secretory vesicles dock and transiently fuse with specialized, permanent, plasma membrane structures, called porosomes or fusion pores. Porosomes are supramolecular, cup-shaped lipoprotein structures at the cell plasma membrane that mediate and control the release of vesicle cargo to the outside of the cell. The sizes of porosomes range from 150nm in diameter in acinar cells of the exocrine pancreas to 12nm in neurons. In recent years, significant progress has been made in our understanding of the porosome and the cellular activities required for cell secretion, such as membrane fusion and swelling of secretory vesicles. The discovery of the porosome complex and the molecular mechanism of cell secretion are summarized in this article.

Membrane protein import in yeast mitochondria

2000 ◽  
Vol 28 (4) ◽  
pp. 495-499 ◽  
Author(s):  
K. Tokatlidis ◽  
S. Vial ◽  
P. Luciano ◽  
M. Vergnolle ◽  
S. Clémence
Keyword(s):  
Membrane Protein ◽  
Molecular Mechanism ◽  
Protein Import ◽  
Mitochondrial Matrix ◽  
Yeast Mitochondria ◽  
Inner Membrane ◽  
Protein Insertion ◽  
The Past ◽  
Membrane Protein Insertion ◽  
Membrane Bound

The protein import pathway that targets proteins to the mitochondrial matrix has been extensively characterized in the past 15 years. Variations of this import pathway account for the sorting of proteins to other compartments as well, but the insertion of integral inner membrane proteins lacking a presequence is mediated by distinct translocation machinery. This consists of a complex of Tim9 and Tim10, two homologous, Zn2+-binding proteins that chaperone the passage of the hydrophobic precursor across the aqueous inter-membrane space. The precursor is then targeted to another, inner-membrane-bound, complex of at least five subunits that facilitates insertion. Biochemical and genetic experiments have identified the key components of this process; we are now starting to understand the molecular mechanism. This review highlights recent advances in this new membrane protein insertion pathway.

scholarly journals VIB-1 Is Required for Expression of Genes Necessary for Programmed Cell Death in Neurospora crassa

2006 ◽  
Vol 5 (12) ◽  
pp. 2161-2173 ◽  
Author(s):  
Karine Dementhon ◽  
Gopal Iyer ◽  
N. Louise Glass
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Neurospora Crassa ◽  
Filamentous Fungi ◽  
Somatic Growth ◽  
Genetic Differences ◽  
Extracellular Proteases ◽  
Hyphal Fusion ◽  
Expression Of Genes ◽  
Nonself Recognition

ABSTRACT Nonself recognition during somatic growth is an essential and ubiquitous phenomenon in both prokaryotic and eukaryotic species. In filamentous fungi, nonself recognition is also important during vegetative growth. Hyphal fusion between genetically dissimilar individuals results in rejection of heterokaryon formation and in programmed cell death of the fusion compartment. In filamentous fungi, such as Neurospora crassa, nonself recognition and heterokaryon incompatibility (HI) are regulated by genetic differences at het loci. In N. crassa, mutations at the vib-1 locus suppress nonself recognition and HI mediated by genetic differences at het-c/pin-c, mat, and un-24/het-6. vib-1 is a homolog of Saccharomyces cerevisiae NDT80, which is a transcriptional activator of genes during meiosis. For this study, we determined that vib-1 encodes a nuclear protein and showed that VIB-1 localization varies during asexual reproduction and during HI. vib-1 is required for the expression of genes involved in nonself recognition and HI, including pin-c, tol, and het-6; all of these genes encode proteins containing a HET domain. vib-1 is also required for the production of downstream effectors associated with HI, including the production of extracellular proteases upon carbon and nitrogen starvation. Our data support a model in which mechanisms associated with starvation and nonself recognition/HI are interconnected. VIB-1 is a major regulator of responses to nitrogen and carbon starvation and is essential for the expression of genes involved in nonself recognition and death in N. crassa.

Using membrane stress to our advantage

2007 ◽  
Vol 35 (3) ◽  
pp. 498-501 ◽  
Author(s):  
G.C. Shearman ◽  
G.S. Attard ◽  
A.N. Hunt ◽  
S. Jackowski ◽  
M. Baciu ◽  
...  
Keyword(s):  
Chemical Reactivity ◽  
Dynamic State ◽  
Membrane Mechanics ◽  
Drug Molecules ◽  
Nano Structures ◽  
Internal Forces ◽  
Membrane Bound ◽  
Self Assembled ◽  
And Control

The nature of the bilayer motif coupled with the ability of lipids and proteins to diffuse freely through this structure is crucial to the viability of cells and their ability to compartmentalize domains contained therein. It seems surprising to find then that biological as well as model membranes exist in a dynamic state of mechanical stress. The stresses within such membranes are surprisingly large, typically reaching up to 50 atm (1 atm=101.325 kPa) at the core of the membrane and vary as a function of depth. The uneven distribution of lateral pressures within monolayer leaflets causes them to bend away from or towards the water interface. This can result in the formation of complex, self-assembled mesophases, many of which occur in vivo. Our knowledge of the principles underlying membrane mechanics has reached the point where we are now able to manipulate them and create nano-structures with reasonable predictability. In addition, they can be used both to explain and control the partitioning of amphipathic proteins on to membranes. The dependence of the dynamics of membrane-bound proteins and the chemical reactivity of amphipathic drug molecules on membrane stresses suggests that Nature itself takes advantage of this. Understanding and manipulating these internal forces will be a key element in creating self-assembled, biocompatible, nanoscale cell-like systems.

Two Forms of a Mitochondrial Endonuclease in Neurospora crassa

1975 ◽  
Vol 53 (7) ◽  
pp. 823-825 ◽  
Author(s):  
Charles E. Martin ◽  
Robert P. Wagner
Keyword(s):  
Molecular Weight ◽  
Neurospora Crassa ◽  
Mitochondrial Membrane ◽  
Nuclease Activity ◽  
Inner Mitochondrial Membrane ◽  
Detergent Treatment ◽  
Approximate Molecular Weight ◽  
Membrane Bound

Mitochondrial nuclease activity in Neurospora crassa occurs in membrane-bound and soluble forms in approximately equal proportions. These activities apparently are due to the same enzyme, which has an approximate molecular weight of 120 000. A portion of the insoluble enzyme appears to be associated with the inner mitochondrial membrane and is resistant to solubilization by detergent treatment as well as by physical disruption methods.

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