scholarly journals Faculty Opinions recommendation of Tumor protein D54 defines a new class of intracellular transport vesicles.

2019 ◽  
Author(s):  
Robert Parton
Keyword(s):  
Intracellular Transport ◽  
New Class ◽  
Transport Vesicles

scholarly journals Tumor protein D54 defines a new class of intracellular transport vesicles

2019 ◽  
Vol 219 (1) ◽  
Author(s):  
Gabrielle Larocque ◽  
Penelope J. La-Borde ◽  
Nicholas I. Clarke ◽  
Nicholas J. Carter ◽  
Stephen J. Royle
Keyword(s):  
Membrane Trafficking ◽  
Intracellular Transport ◽  
Super Resolution ◽  
Molecular Heterogeneity ◽  
Rab Gtpases ◽  
New Class ◽  
Transport Vesicles ◽  
Transport Vesicle ◽  
Membrane Compartment ◽  
Generic Class

Transport of proteins and lipids from one membrane compartment to another is via intracellular vesicles. We investigated the function of tumor protein D54 (TPD54/TPD52L2) and found that TPD54 was involved in multiple membrane trafficking pathways: anterograde traffic, recycling, and Golgi integrity. To understand how TPD54 controls these diverse functions, we used an inducible method to reroute TPD54 to mitochondria. Surprisingly, this manipulation resulted in the capture of many small vesicles (30 nm diameter) at the mitochondrial surface. Super-resolution imaging confirmed the presence of similarly sized TPD54-positive structures under normal conditions. It appears that TPD54 defines a new class of transport vesicle, which we term intracellular nanovesicles (INVs). INVs meet three criteria for functionality. They contain specific cargo, they have certain R-SNAREs for fusion, and they are endowed with a variety of Rab GTPases (16 out of 43 tested). The molecular heterogeneity of INVs and the diverse functions of TPD54 suggest that INVs have various membrane origins and a number of destinations. We propose that INVs are a generic class of transport vesicle that transfer cargo between these varied locations.

scholarly journals Neuronal receptors display cytoskeleton-independent directed motion on the plasma membrane

2018 ◽  
Author(s):  
R. D. Taylor ◽  
M. Heine ◽  
N. J. Emptage ◽  
L. C. Andreae
Keyword(s):  
Plasma Membrane ◽  
Neuronal Activity ◽  
Particle Tracking ◽  
Hippocampal Neurons ◽  
Intracellular Transport ◽  
Transmembrane Proteins ◽  
Single Particle Tracking ◽  
Directed Motion ◽  
Surface Movement ◽  
Transport Vesicles

AbstractDirected transport of transmembrane proteins is generally believed to occur via intracellular transport vesicles. However, using single particle tracking in rat hippocampal neurons with a pH-sensitive quantum dot probe which specifically reports surface movement of receptors, we have identified a subpopulation of neuronal EphB2 receptors that exhibit directed motion between synapses within the plasma membrane itself. This receptor movement occurs independently of the cytoskeleton but is dependent on cholesterol and is regulated by neuronal activity.

scholarly journals Rab GDI: a solubilizing and recycling factor for rab9 protein.

1993 ◽  
Vol 4 (4) ◽  
pp. 425-434 ◽  
Author(s):  
T Soldati ◽  
M A Riederer ◽  
S R Pfeffer
Keyword(s):  
Complex Formation ◽  
Intracellular Transport ◽  
Rab Proteins ◽  
Rab Protein ◽  
Transport Vesicles ◽  
Late Endosomes ◽  
Geranylgeranyl Transferase ◽  
Carboxy Terminal ◽  
Golgi Network

Rab proteins are thought to function in the processes by which transport vesicles identify and/or fuse with their respective target membranes. The bulk of these proteins are membrane associated, but a measurable fraction can be found in the cytosol. The cytosolic forms of rab3A, rab11, and Sec4 occur as equimolar complexes with a class of proteins termed "GDIs," or "GDP dissociation inhibitors." We show here that the cytosolic form of rab9, a protein required for transport between late endosomes and the trans Golgi network, also occurs as a complex with a GDI-like protein, with an apparent mass of approximately 80 kD. Complex formation could be reconstituted in vitro using recombinant rab9 protein, cytosol, ATP, and geranylgeranyl diphosphate, and was shown to require an intact rab9 carboxy terminus, as well as rab9 geranylgeranylation. Monoprenylation was sufficient for complex formation because a mutant rab9 protein bearing the carboxy terminal sequence, CLLL, was prenylated in vitro by geranylgeranyl transferase I and was efficiently incorporated into 80-kD complexes. Purified, prenylated rab9 could also assemble into 80-kD complexes by addition of purified, rab3A GDI. Finally, rab3A-GDI had the capacity to solubilize rab9GDP, but not rab9GTP, from cytoplasmic membranes. These findings support the proposal that GDI proteins serve to recycle rab proteins from their target membranes after completion of a rab protein-mediated, catalytic cycle. Thus GDI proteins have the potential to regulate the availability of specific intracellular transport factors.

scholarly journals A New Syntaxin Family Member Implicated in Targeting of Intracellular Transport Vesicles

1996 ◽  
Vol 271 (30) ◽  
pp. 17961-17965 ◽  
Author(s):  
Jason B. Bock ◽  
Richard C. Lin ◽  
Richard H. Scheller
Keyword(s):  
Family Member ◽  
Intracellular Transport ◽  
Transport Vesicles

scholarly journals Novel syntaxin homologue, Pep12p, required for the sorting of lumenal hydrolases to the lysosome-like vacuole in yeast.

1996 ◽  
Vol 7 (4) ◽  
pp. 579-594 ◽  
Author(s):  
K A Becherer ◽  
S E Rieder ◽  
S D Emr ◽  
E W Jones
Keyword(s):  
Intracellular Transport ◽  
Sequence Similarity ◽  
Integral Membrane Protein ◽  
Subcellular Fractionation ◽  
Hydrophobic Region ◽  
Significant Sequence Similarity ◽  
Transport Vesicles ◽  
Class D ◽  
A Minor ◽  
35 Kda Protein

pep12/vps6 mutants of Saccharomyces cerevisiae are defective in delivery of soluble vacuolar hydrolases to the vacuole. Morphological analysis by electron microscopy revealed that pep12 cells accumulate 40- to 50-nm vesicles. Furthermore, pep12 cells have enlarged vacuoles characteristic of class D pep/vps mutants. PEP12 encodes a protein of 288 amino acids that has a C-terminal hydrophobic region and shares significant sequence similarity with members of the syntaxin protein family. These proteins appear to participate in the docking and fusion of intracellular transport vesicles. Pep12p is the first member of the syntaxin family to be implicated in transport between the Golgi and the vacuole/lysosome. Pep12p-specific polyclonal antisera detected a 35-kDa protein that fractionated as an integral membrane protein. Subcellular fractionation experiments revealed that Pep12p was associated with membrane fractions of two different densities; the major pool (approximately 90%) of pep12p may associate with the endosome, while a minor pool (approximately 10%) cofractionated with the late Golgi marker Kex2p. These observations suggest that Pep12p may mediate the docking of Golgi-derived transport vesicles at the endosome.

scholarly journals Adaptins

2001 ◽  
Vol 12 (10) ◽  
pp. 2907-2920 ◽  
Author(s):  
Markus Boehm ◽  
Juan S. Bonifacino
Keyword(s):  
Arabidopsis Thaliana ◽  
Intracellular Transport ◽  
Adaptor Protein ◽  
Fruit Fly ◽  
C Elegans ◽  
Transport Vesicles ◽  
Intron Structure ◽  
Related Proteins ◽  
Selection Of ◽  
Plant Arabidopsis Thaliana

Adaptins are subunits of adaptor protein (AP) complexes involved in the formation of intracellular transport vesicles and in the selection of cargo for incorporation into the vesicles. In this article, we report the results of a survey for adaptins from sequenced genomes including those of man, mouse, the fruit fly Drosophila melanogaster, the nematode Caenorhabditis elegans, the plant Arabidopsis thaliana, and the yeasts, Saccharomyces cerevisiae andSchizosaccharomyces pombe. We find that humans, mice, and Arabidopsis thaliana have four AP complexes (AP-1, AP-2, AP-3, and AP-4), whereas D. melanogaster,C. elegans, S. cerevisiae, and S. pombe have only three (AP-1, AP-2, and AP-3). Additional diversification of AP complexes arises from the existence of adaptin isoforms encoded by distinct genes or resulting from alternative splicing of mRNAs. We complete the assignment of adaptins to AP complexes and provide information on the chromosomal localization, exon-intron structure, and pseudogenes for the different adaptins. In addition, we discuss the structural and evolutionary relationships of the adaptins and the genetic analyses of their function. Finally, we extend our survey to adaptin-related proteins such as the GGAs and stonins, which contain domains homologous to the adaptins.

scholarly journals Multiple functions of inositolphosphorylceramides in the formation and intracellular transport of glycosylphosphatidylinositol-anchored proteins in yeast

2007 ◽  
Vol 74 ◽  
pp. 199-209 ◽  
Author(s):  
Régine Bosson ◽  
Andreas Conzelmann
Keyword(s):  
Fatty Acids ◽  
Endoplasmic Reticulum ◽  
Fatty Acid ◽  
Intracellular Transport ◽  
Secretory Pathway ◽  
Gpi Anchor ◽  
New Class ◽  
Golgi Transport ◽  
Lipid Moiety ◽  
Gpi Proteins

The mature sphingolipids of yeast consist of IPCs (inositolphosphorylceramides) and glycosylated derivatives thereof. Beyond being an abundant membrane constituent in the organelles of the secretory pathway, IPCs are also used to constitute the lipid moiety of the majority of GPI (glycosylphosphatidylinositol) proteins, while a minority of GPI proteins contain PI (phosphatidylinositol). Thus all GPI anchor lipids (as well as free IPCs) typically contain C26 fatty acids. However, the primary GPI lipid that isadded to newly synthesized proteins in the endoplasmic reticulum consists of a PI with conventional C16 and C18 fatty acids. A new class of enzymes is required to replace the fatty acid in sn-2 by a C26 fatty acid. Cells lacking this activity make normal amounts of GPI proteins but accumulate GPI anchors containing lyso-PI. As a consequence, the endoplasmic reticulum to Golgi transport of the GPI protein Gas1p is slow, and mature Gas1p is lost from the plasma membrane into the medium. The GPI anchor containing C26 in sn-2 can further be remodelled by the exchange of diacylglycerol for ceramide. This process is also dependent on the presence of specific phosphorylethanolamine side-chains on the GPI anchor.

Sign in / Sign up

Export Citation Format

Share Document