Faculty Opinions recommendation of Signal peptide-chaperone interactions on the twin-arginine protein transport pathway.

Neo1p from Saccharomyces cerevisiae is an essential P-type ATPase and potential aminophospholipid translocase (flippase) in the Drs2p family. We have previously implicated Drs2p in protein transport steps in the late secretory pathway requiring ADP-ribosylation factor (ARF) and clathrin. Here, we present evidence that epitope-tagged Neo1p localizes to the endoplasmic reticulum (ER) and Golgi complex and is required for a retrograde transport pathway between these organelles. Using conditional alleles of NEO1, we find that loss of Neo1p function causes cargo-specific defects in anterograde protein transport early in the secretory pathway and perturbs glycosylation in the Golgi complex. Rer1-GFP, a protein that cycles between the ER and Golgi complex in COPI and COPII vesicles, is mislocalized to the vacuole in neo1-ts at the nonpermissive temperature. These phenotypes suggest that the anterograde protein transport defect is a secondary consequence of a defect in a COPI-dependent retrograde pathway. We propose that loss of lipid asymmetry in the cis Golgi perturbs retrograde protein transport to the ER.

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Functional assembly of thylakoid ΔpH-dependent/Tat protein transport pathway componentsin vitro

European Journal of Biochemistry ◽

10.1046/j.1432-1033.2003.03894.x ◽

2003 ◽

Vol 270 (24) ◽

pp. 4930-4941 ◽

Cited By ~ 32

Author(s):

Vivian Fincher ◽

Carole Dabney-Smith ◽

Kenneth Cline

Keyword(s):

Protein Transport ◽

Tat Protein ◽

Transport Pathway

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Import into and Degradation of Cytosolic Proteins by Isolated Yeast Vacuoles

Molecular Biology of the Cell ◽

10.1091/mbc.10.9.2879 ◽

1999 ◽

Vol 10 (9) ◽

pp. 2879-2889 ◽

Cited By ~ 27

Author(s):

Martin Horst ◽

Erwin C. Knecht ◽

Peter V. Schu

Keyword(s):

Mammalian Cells ◽

Protein Transport ◽

Protein Import ◽

Degradation Pathway ◽

Specific Protein ◽

Transport Pathway ◽

Cytosolic Proteins ◽

Hsp70 Family ◽

Vacuolar Protein ◽

Shock Proteins

In eukaryotic cells, both lysosomal and nonlysosomal pathways are involved in degradation of cytosolic proteins. The physiological condition of the cell often determines the degradation pathway of a specific protein. In this article, we show that cytosolic proteins can be taken up and degraded by isolated Saccharomyces cerevisiae vacuoles. After starvation of the cells, protein uptake increases. Uptake and degradation are temperature dependent and show biphasic kinetics. Vacuolar protein import is dependent on cytosolic heat shock proteins of the hsp70 family and on protease-sensitive component(s) on the outer surface of vacuoles. Degradation of the imported cytosolic proteins depends on a functional vacuolar ATPase. We show that the cytosolic isoform of yeast glyceraldehyde-3-phosphate dehydrogenase is degraded via this pathway. This import and degradation pathway is reminiscent of the protein transport pathway from the cytosol to lysosomes of mammalian cells.

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Lateral transport of Smoothened from the plasma membrane to the membrane of the cilium

The Journal of Cell Biology ◽

10.1083/jcb.200907126 ◽

2009 ◽

Vol 187 (3) ◽

pp. 365-374 ◽

Cited By ~ 186

Author(s):

Ljiljana Milenkovic ◽

Matthew P. Scott ◽

Rajat Rohatgi

Keyword(s):

Plasma Membrane ◽

Protein Trafficking ◽

Primary Cilia ◽

Protein Transport ◽

Transmembrane Protein ◽

Signaling Proteins ◽

Lateral Transport ◽

Transport Pathway ◽

Ciliary Membrane ◽

Specific Proteins

The function of primary cilia depends critically on the localization of specific proteins in the ciliary membrane. A major challenge in the field is to understand protein trafficking to cilia. The Hedgehog (Hh) pathway protein Smoothened (Smo), a 7-pass transmembrane protein, moves to cilia when a ligand is received. Using microscopy-based pulse-chase analysis, we find that Smo moves through a lateral transport pathway from the plasma membrane to the ciliary membrane. Lateral movement, either via diffusion or active transport, is quite distinct from currently studied pathways of ciliary protein transport in mammals, which emphasize directed trafficking of Golgi-derived vesicles to the base of the cilium. We anticipate that this alternative route will be used by other signaling proteins that function at cilia. The path taken by Smo may allow novel strategies for modulation of Hh signaling in cancer and regeneration.

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Annotating eukaryotic and toxin-specific signal peptides using Razor

10.1101/2020.11.30.405613 ◽

2020 ◽

Author(s):

Bikash K. Bhandari ◽

Paul P. Gardner ◽

Chun Shen Lim

Keyword(s):

Signal Peptide ◽

Web Application ◽

Protein Transport ◽

Protein Translocation ◽

Recombinant Protein Expression ◽

Disease Diagnosis ◽

Signal Peptides ◽

Specific Signal ◽

Link Type ◽

Command Line Tool

ABSTRACTMotivationSignal peptides are responsible for protein transport and secretion and are ubiquitous to all forms of life. The annotation of signal peptides is important for understanding protein translocation and toxin secretion, optimising recombinant protein expression, as well as for disease diagnosis and metagenomics.ResultsHere we explore the features of these signal sequences across eukaryotes. We find that different kingdoms have their characteristic distributions of signal peptide residues. Additionally, the signal peptides of secretory toxins have common features across kingdoms. We leverage these subtleties to build Razor, a simple yet powerful tool for annotating signal peptides, which additionally predicts toxin- and fungal-specific signal peptides based on the first 23 N-terminal residues. Finally, we demonstrate the usability of Razor by scanning all reviewed sequences from UniProt. Indeed, Razor is able to identify toxins using their signal peptide sequences only. Strikingly, we discover that many defensive proteins across kingdoms harbour a toxin-like signal peptide; some of these defensive proteins have emerged through convergent evolution, e.g. defensin and defensin-like protein families, and phospholipase families.Availability and implementationRazor is available as a web application (https://tisigner.com/razor) and a command-line tool (https://github.com/Gardner-BinfLab/Razor).

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Thylakoid-integrated recombinant Hcf106 participates in the chloroplast Twin Arginine Transport (cpTat) system

10.1101/382812 ◽

2018 ◽

Author(s):

Qianqian Ma ◽

Kristen Fite ◽

Christopher Paul New ◽

Carole Dabney-Smith

Keyword(s):

Protein Transport ◽

Transmembrane Domain ◽

Polyacrylamide Gel Electrophoresis ◽

Sole Source ◽

Receptor Complex ◽

Amphipathic Helix ◽

Transport Pathway ◽

Independent Manner ◽

Arginine Transport

AbstractThe chloroplast Twin arginine transport (cpTat) system distinguishes itself as a protein transport pathway by translocating fully-folded proteins, using the proton-motive force (PMF) as the sole source of energy. The cpTat pathway is evolutionarily conserved with the Tat pathway found in the plasma membrane of many prokaryotes. The cpTat (E. coli) system uses three proteins, Tha4 (TatA), Hcf106 (TatB), and cpTatC (TatC), to form a transient translocase allowing the passage of precursor proteins. Briefly, cpTatC and Hcf106, with Tha4, form the initial receptor complex responsible for precursor protein recognition and binding in an energy-independent manner, while a separate pool of Tha4 assembles with the precursor-bound receptor complex in the presence the PMF. Analysis by blue-native polyacrylamide gel electrophoresis (BN-PAGE) shows that the receptor complex, in the absence of precursor, migrates near 700 kDa and contains cpTatC and Hcf106 with little Tha4 remaining after detergent solubilization. To investigate the role that Hcf106 may play in receptor complex oligomerization and/or stability, systematic cysteine substitutions were made in positions from the N-terminal transmembrane domain to the end of the predicted amphipathic helix of the protein. BN-PAGE analysis allowed us to identify the locations of amino acids in Hcf106 that were critical for interacting with cpTatC. Oxidative cross-linking allowed us to map interactions of the transmembrane domain and amphipathic helix region of Hcf106. In addition, we showed that in vitro expressed, integrated Hcf106 can interact with the precursor signal peptide domain and imported cpTatC, strongly suggesting that a subpopulation of the integrated Hcf106 is participating in competent cpTat complexes.

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Vacuole Biogenesis in Saccharomyces cerevisiae: Protein Transport Pathways to the Yeast Vacuole

Microbiology and Molecular Biology Reviews ◽

10.1128/mmbr.62.1.230-247.1998 ◽

1998 ◽

Vol 62 (1) ◽

pp. 230-247 ◽

Cited By ~ 191

Author(s):

Nia J. Bryant ◽

Tom H. Stevens

Keyword(s):

Saccharomyces Cerevisiae ◽

Protein Delivery ◽

Secretory Pathway ◽

Protein Transport ◽

Transport Pathway ◽

Yeast Saccharomyces Cerevisiae ◽

Transport Pathways ◽

Yeast Vacuole ◽

Lysosome Biogenesis ◽

Vacuolar Protein

SUMMARY Delivery of proteins to the vacuole of the yeast Saccharomyces cerevisiae provides an excellent model system in which to study vacuole and lysosome biogenesis and membrane traffic. This organelle receives proteins from a number of different routes, including proteins sorted away from the secretory pathway at the Golgi apparatus and endocytic traffic arising from the plasma membrane. Genetic analysis has revealed at least 60 genes involved in vacuolar protein sorting, numerous components of a novel cytoplasm-to-vacuole transport pathway, and a large number of proteins required for autophagy. Cell biological and biochemical studies have provided important molecular insights into the various protein delivery pathways to the yeast vacuole. This review describes the various pathways to the vacuole and illustrates how they are related to one another in the vacuolar network of S. cerevisiae.

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