scholarly journals Membrane Traffic in Aspergillus oryzae and Related Filamentous Fungi

2021 ◽  
Vol 7 (7) ◽  
pp. 534
Author(s):  
Yujiro Higuchi
Keyword(s):  
Filamentous Fungi ◽  
Aspergillus Oryzae ◽  
Protein Secretion ◽  
Membrane Trafficking ◽  
Secretory Pathway ◽  
Molecular Mechanisms ◽  
Membrane Traffic ◽  
Industrial Applications ◽  
Endocytic Pathway ◽  
Great Ability

The industrially important filamentous fungus Aspergillus oryzae, known as the yellow Koji mold and also designated the Japanese National fungus, has been investigated for understanding the intracellular membrane trafficking machinery due to the great ability of valuable enzyme production. The underlying molecular mechanisms of the secretory pathway delineate the main secretion route from the hyphal tip via the vesicle cluster Spitzenkörper, but also there is a growing body of evidence that septum-directed and unconventional secretion occurs in A. oryzae hyphal cells. Moreover, not only the secretory pathway but also the endocytic pathway is crucial for protein secretion, especially having a role in apical endocytic recycling. As a hallmark of multicellular filamentous fungal cells, endocytic organelles early endosome and vacuole are quite dynamic: the former exhibits constant long-range motility through the hyphal cells and the latter displays pleiomorphic structures in each hyphal region. These characteristics are thought to have physiological roles, such as supporting protein secretion and transporting nutrients. This review summarizes molecular and physiological mechanisms of membrane traffic, i.e., secretory and endocytic pathways, in A. oryzae and related filamentous fungi and describes the further potential for industrial applications.

Membrane traffic related to endosome dynamics and protein secretion in filamentous fungi

2021 ◽  
Author(s):  
Yujiro Higuchi
Keyword(s):  
Filamentous Fungi ◽  
Protein Secretion ◽  
Secretory Pathway ◽  
Molecular Mechanisms ◽  
Membrane Traffic ◽  
Early Endosome ◽  
Protein Glycosylation ◽  
Hyphal Cell ◽  
Cell Factories ◽  
Membrane Contacts

ABSTRACT In eukaryotic cells, membrane-surrounded organelles are orchestrally organized spatiotemporally under environmental situations. Among such organelles, vesicular transports and membrane contacts occur to communicate each other, so-called membrane traffic. Filamentous fungal cells are highly polarized and thus membrane traffic is developed to have versatile functions. Early endosome (EE) is an endocytic organelle that dynamically exhibits constant long-range motility through the hyphal cell, which is proven to have physiological roles, such as other organelle distribution and signal transduction. Since filamentous fungal cells are also considered as cell factories, to produce valuable proteins extracellularly, molecular mechanisms of secretory pathway including protein glycosylation have been well investigated. In this review, molecular and physiological aspects of membrane traffic especially related to EE dynamics and protein secretion in filamentous fungi are summarized, and perspectives for application are also described.

scholarly journals Genetic Ablation of Phosphatidylinositol Transfer Protein Function in Murine Embryonic Stem Cells

2002 ◽  
Vol 13 (3) ◽  
pp. 739-754 ◽  
Author(s):  
James G. Alb ◽  
Scott E. Phillips ◽  
Kathleen Rostand ◽  
Xiaoxia Cui ◽  
Jef Pinxteren ◽  
...  
Keyword(s):  
Mast Cell ◽  
Membrane Trafficking ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Embryonic Stem ◽  
Endocytic Pathway ◽  
Dense Core ◽  
Homologous Proteins ◽  
Genetic Ablation ◽  
Phosphatidylinositol Transfer

Phosphatidylinositol transfer proteins (PITPs) regulate the interface between signal transduction, membrane-trafficking, and lipid metabolic pathways in eukaryotic cells. The best characterized mammalian PITPs are PITPα and PITPβ, two highly homologous proteins that are encoded by distinct genes. Insights into PITPα and PITPβ function in mammalian systems have been gleaned exclusively from cell-free or permeabilized cell reconstitution and resolution studies. Herein, we report for the first time the use of genetic approaches to directly address the physiological functions of PITPα and PITPβ in murine cells. Contrary to expectations, we find that ablation of PITPα function in murine cells fails to compromise growth and has no significant consequence for bulk phospholipid metabolism. Moreover, the data show that PITPα does not play an obvious role in any of the cellular activities where it has been reconstituted as an essential stimulatory factor. These activities include protein trafficking through the constitutive secretory pathway, endocytic pathway function, biogenesis of mast cell dense core secretory granules, and the agonist-induced fusion of dense core secretory granules to the mast cell plasma membrane. Finally, the data demonstrate that PITPα-deficient cells not only retain their responsiveness to bulk growth factor stimulation but also retain their pluripotency. In contrast, we were unable to evict both PITPβ alleles from murine cells and show that PITPβ deficiency results in catastrophic failure early in murine embryonic development. We suggest that PITPβ is an essential housekeeping PITP in murine cells, whereas PITPα plays a far more specialized function in mammals than that indicated by in vitro systems that show PITP dependence.

The role of regulated CFTR trafficking in epithelial secretion

2003 ◽  
Vol 285 (1) ◽  
pp. C1-C18 ◽  
Author(s):  
Carol A. Bertrand ◽  
Raymond A. Frizzell
Keyword(s):  
Epithelial Cells ◽  
Membrane Trafficking ◽  
Cellular Localization ◽  
Secretory Pathway ◽  
Molecular Mechanisms ◽  
Experimental Manipulation ◽  
Experimental Conditions ◽  
Functional Studies ◽  
Cellular Context ◽  
Polarized Epithelial Cells

The focus of this review is the regulated trafficking of the cystic fibrosis transmembrane conductance regulator (CFTR) in distal compartments of the protein secretory pathway and the question of how changes in CFTR cellular distribution may impact on the functions of polarized epithelial cells. We summarize data concerning the cellular localization and activity of CFTR and attempt to synthesize often conflicting results from functional studies of regulated endocytosis and exocytosis in CFTR-expressing cells. In some instances, findings that are inconsistent with regulated CFTR trafficking may result from the use of overexpression systems or nonphysiological experimental conditions. Nevertheless, judging from data on other transporters, an appropriate cellular context is necessary to support regulated CFTR trafficking, even in epithelial cells. The discovery that disease mutations can influence CFTR trafficking in distal secretory and recycling compartments provides support for the concept that regulated CFTR recycling contributes to normal epithelial function, including the control of apical CFTR channel density and epithelial protein secretion. Finally, we propose molecular mechanisms for regulated CFTR endocytosis and exocytosis that are based on CFTR interactions with other proteins, particularly those whose primary function is membrane trafficking. These models provide testable hypotheses that may lead to elucidation of CFTR trafficking mechanisms and permit their experimental manipulation in polarized epithelial cells.

scholarly journals Vacuole Membrane Protein 1 Is an Endoplasmic Reticulum Protein Required for Organelle Biogenesis, Protein Secretion, and Development

2008 ◽  
Vol 19 (8) ◽  
pp. 3442-3453 ◽  
Author(s):  
Javier Calvo-Garrido ◽  
Sergio Carilla-Latorre ◽  
Francisco Lázaro-Diéguez ◽  
Gustavo Egea ◽  
Ricardo Escalante
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Protein ◽  
Protein Secretion ◽  
Secretory Pathway ◽  
Endocytic Pathway ◽  
Organelle Biogenesis ◽  
Loss Of Function ◽  
Vacuole Membrane ◽  
Genomic Study ◽  
Endoplasmic Reticulum Protein

Vacuole membrane protein 1 (Vmp1) is membrane protein of unknown molecular function that has been associated with pancreatitis and cancer. The social amoeba Dictyostelium discoideum has a vmp1-related gene that we identified previously in a functional genomic study. Loss-of-function of this gene leads to a severe phenotype that compromises Dictyostelium growth and development. The expression of mammalian Vmp1 in a vmp1− Dictyostelium mutant complemented the phenotype, suggesting a functional conservation of the protein among evolutionarily distant species and highlights Dictyostelium as a valid experimental system to address the function of this gene. Dictyostelium Vmp1 is an endoplasmic reticulum protein necessary for the integrity of this organelle. Cells deficient in Vmp1 display pleiotropic defects in the secretory pathway and organelle biogenesis. The contractile vacuole, which is necessary to survive under hypoosmotic conditions, is not functional in the mutant. The structure of the Golgi apparatus, the function of the endocytic pathway and conventional protein secretion are also affected in these cells. Transmission electron microscopy of vmp1− cells showed the accumulation of autophagic features that suggests a role of Vmp1 in macroautophagy. In addition to these defects observed at the vegetative stage, the onset of multicellular development and early developmental gene expression are also compromised.

Phosphoinositides and membrane traffic at the trans-Golgi network.

2005 ◽  
Vol 72 ◽  
pp. 31-38 ◽  
Author(s):  
Rawshan R. Choudhury ◽  
Noora Hyvola ◽  
Martin Lowe
Keyword(s):  
Plasma Membrane ◽  
Secretory Pathway ◽  
Binding Proteins ◽  
Molecular Mechanisms ◽  
Membrane Traffic ◽  
Trans Golgi Network ◽  
Cargo Proteins ◽  
Golgi Network

Cargo proteins moving along the secretory pathway are sorted at the TGN (trans-Golgi network) into distinct carriers for delivery to the plasma membrane or endosomes. Recent studies in yeast and mammals have shown that formation of these carriers is regulated by PtdIns(4)P. This phosphoinositide is abundant at the TGN and acts to recruit components required for carrier formation to the membrane. Other phosphoinositides are also present on the TGN, but the extent to which they regulate trafficking is less clear. Further characterization of phosphoinositide kinases and phosphatases together with identification of new TGN-associated phosphoinositide-binding proteins will reveal the extent to which different phosphoinositides regulate TGN trafficking, and help define the molecular mechanisms involved.

scholarly journals A Yeast t-SNARE Involved in Endocytosis

1998 ◽  
Vol 9 (10) ◽  
pp. 2873-2889 ◽  
Author(s):  
Karin Séron ◽  
Ville Tieaho ◽  
Cristina Prescianotto-Baschong ◽  
Thomas Aust ◽  
Marie-Odile Blondel ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Secretory Pathway ◽  
Essential Gene ◽  
Specific Interaction ◽  
Endocytic Pathway ◽  
Intracellular Membrane ◽  
Atpase Subunit ◽  
Early Endosomes ◽  
Endocytic Vesicles ◽  
Positively Charged

The ORF YOL018c (TLG2) of Saccharomyces cerevisiae encodes a protein that belongs to the syntaxin protein family. The proteins of this family, t-SNAREs, are present on target organelles and are thought to participate in the specific interaction between vesicles and acceptor membranes in intracellular membrane trafficking. TLG2 is not an essential gene, and its deletion does not cause defects in the secretory pathway. However, its deletion in cells lacking the vacuolar ATPase subunit Vma2p leads to loss of viability, suggesting that Tlg2p is involved in endocytosis. In tlg2Δ cells, internalization was normal for two endocytic markers, the pheromone α-factor and the plasma membrane uracil permease. In contrast, degradation of α-factor and uracil permease was delayed intlg2Δ cells. Internalization of positively charged Nanogold shows that the endocytic pathway is perturbed in the mutant, which accumulates Nanogold in primary endocytic vesicles and shows a greatly reduced complement of early endosomes. These results strongly suggest that Tlg2p is a t-SNARE involved in early endosome biogenesis.

scholarly journals A novel fluorescence-activated cell sorter-based screen for yeast endocytosis mutants identifies a yeast homologue of mammalian eps15.

1996 ◽  
Vol 135 (6) ◽  
pp. 1485-1500 ◽  
Author(s):  
B Wendland ◽  
J M McCaffery ◽  
Q Xiao ◽  
S D Emr
Keyword(s):  
Protein Interactions ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Screening Strategy ◽  
Endocytic Pathway ◽  
Temperature Sensitive ◽  
Filamentous Actin ◽  
Early Endosomes ◽  
Yeast Mutants

A complete understanding of the molecular mechanisms of endocytosis requires the discovery and characterization of the protein machinery that mediates this aspect of membrane trafficking. A novel genetic screen was used to identify yeast mutants defective in internalization of bulk lipid. The fluorescent lipophilic styryl dye FM4-64 was used in conjunction with FACS to enrich for yeast mutants that exhibit internalization defects. Detailed characterization of two of these mutants, dim1-1 and dim2-1, revealed defects in the endocytic pathway. Like other yeast endocytosis mutants, the temperature-sensitive dim mutant were unable to endocytose FM4-64 or radiolabeled alpha-factor as efficiently as wild-type cells. In addition, double mutants with either dim1-delta or dim2-1 and the endocytosis mutants end4-1 or act1-1 displayed synthetic growth defects, indicating that the DIM gene products function in a common or parallel endocytic pathway. Complementation cloning of the DIM genes revealed identity of DIM1 to SHE4 and DIM2 to PAN1. Pan1p shares homology with the mammalian clathrin adaptor-associated protein, eps15. Both proteins contain multiple EH (eps15 homology) domains, a motif proposed to mediate protein-protein interactions. Phalloidin labeling of filamentous actin revealed profound defects in the actin cytoskeleton in both dim mutants. EM analysis revealed that the dim mutants accumulate vesicles and tubulo-vesicular structures reminiscent of mammalian early endosomes. In addition, the accumulation of novel plasma membrane invaginations where endocytosis is likely to occur were visualized in the mutants by electron microscopy using cationized ferritin as a marker for the endocytic pathway. This new screening strategy demonstrates a role for She4p and Pan1p in endocytosis, and provides a new general method for the identification of additional endocytosis mutants.

scholarly journals Divergence of a genomic island leads to the evolution of melanization in a halophyte root fungus

2021 ◽  
Author(s):  
Zhilin Yuan ◽  
Irina S. Druzhinina ◽  
John G. Gibbons ◽  
Zhenhui Zhong ◽  
Yves Van de Peer ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Genomic Island ◽  
Population Genomics ◽  
Growth Yield ◽  
Fixation Index ◽  
Nucleotide Polymorphisms ◽  
Evolutionary Mechanisms ◽  
Melanin Biosynthesis ◽  
Two Populations

AbstractUnderstanding how organisms adapt to extreme living conditions is central to evolutionary biology. Dark septate endophytes (DSEs) constitute an important component of the root mycobiome and they are often able to alleviate host abiotic stresses. Here, we investigated the molecular mechanisms underlying the beneficial association between the DSE Laburnicola rhizohalophila and its host, the native halophyte Suaeda salsa, using population genomics. Based on genome-wide Fst (pairwise fixation index) and Vst analyses, which compared the variance in allele frequencies of single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs), respectively, we found a high level of genetic differentiation between two populations. CNV patterns revealed population-specific expansions and contractions. Interestingly, we identified a ~20 kbp genomic island of high divergence with a strong sign of positive selection. This region contains a melanin-biosynthetic polyketide synthase gene cluster linked to six additional genes likely involved in biosynthesis, membrane trafficking, regulation, and localization of melanin. Differences in growth yield and melanin biosynthesis between the two populations grown under 2% NaCl stress suggested that this genomic island contributes to the observed differences in melanin accumulation. Our findings provide a better understanding of the genetic and evolutionary mechanisms underlying the adaptation to saline conditions of the L. rhizohalophila–S. salsa symbiosis.

scholarly journals Genetic analysis of amyotrophic lateral sclerosis identifies contributing pathways and cell types

2021 ◽  
Vol 7 (3) ◽  
pp. eabd9036
Author(s):  
Sara Saez-Atienzar ◽  
Sara Bandres-Ciga ◽  
Rebekah G. Langston ◽  
Jonggeol J. Kim ◽  
Shing Wan Choi ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Polygenic Risk Score ◽  
Genome Wide ◽  
Genome Wide Data ◽  
Data Driven Approach ◽  
Single Nucleus ◽  
Lateral Sclerosis

Despite the considerable progress in unraveling the genetic causes of amyotrophic lateral sclerosis (ALS), we do not fully understand the molecular mechanisms underlying the disease. We analyzed genome-wide data involving 78,500 individuals using a polygenic risk score approach to identify the biological pathways and cell types involved in ALS. This data-driven approach identified multiple aspects of the biology underlying the disease that resolved into broader themes, namely, neuron projection morphogenesis, membrane trafficking, and signal transduction mediated by ribonucleotides. We also found that genomic risk in ALS maps consistently to GABAergic interneurons and oligodendrocytes, as confirmed in human single-nucleus RNA-seq data. Using two-sample Mendelian randomization, we nominated six differentially expressed genes (ATG16L2, ACSL5, MAP1LC3A, MAPKAPK3, PLXNB2, and SCFD1) within the significant pathways as relevant to ALS. We conclude that the disparate genetic etiologies of this fatal neurological disease converge on a smaller number of final common pathways and cell types.

scholarly journals Transcriptome and proteome analysis suggest enhanced photosynthesis in tetraploid Liriodendron sino-americanum

2021 ◽  
Author(s):  
Tingting Chen ◽  
Yu Sheng ◽  
Zhaodong Hao ◽  
Xiaofei Long ◽  
Fangfang Fu ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Protein Complexes ◽  
Proteome Analysis ◽  
Tree Height ◽  
Photosynthetic Electron Transport ◽  
Industrial Applications ◽  
Chlorophyll Protein Complexes ◽  
Chlorophyll Protein ◽  
Photosynthesis Genes ◽  
Underlying Mechanisms

Abstract Polyploidy generally provides an advantage in phenotypic variation and growth vigor. However, the underlying mechanisms remain poorly understood. The tetraploid L. sino-americanum exhibits altered morphology compared to its diploid counterpart, including larger, thicker and deeper green leaves, bigger stomata, thicker stems and increased tree height. Such characteristics can be useful in ornamental and industrial applications. To elucidate the molecular mechanisms behind this variation, we performed a comparative transcriptome and proteome analysis. Our transcriptome data indicated that some photosynthesis genes and pathways were differentially altered and enriched in tetraploid L. sino-americanum, mainly related to F-type ATPase, the cytochrome b6/f complex, photosynthetic electron transport, the light harvesting chlorophyll protein complexes, photosystem I and II. Most of the differentially expressed proteins we could identify are also involved in photosynthesis. Our physiological results showed that tetraploids have an enhanced photosynthetic capacity, concomitant with great levels of sugar and starch in leaves. This suggests that tetraploid L. sino-americanum might experience comprehensive transcriptome reprogramming of genes related to photosynthesis. This study has especially emphasized molecular changes involved in photosynthesis that accompany polyploidy, and provides a possible explanation for the altered phenotype of polyploidy plants in comparison to their diploid form.

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