scholarly journals BEX5/RabA1b Regulates trans-Golgi Network-to-Plasma Membrane Protein Trafficking in Arabidopsis

2012 ◽  
Vol 24 (7) ◽  
pp. 3074-3086 ◽  
Author(s):  
Elena Feraru ◽  
Mugurel I. Feraru ◽  
Rin Asaoka ◽  
Tomasz Paciorek ◽  
Riet De Rycke ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Protein Trafficking ◽  
Plasma Membrane Protein ◽  
Trans Golgi Network ◽  
Membrane Protein Trafficking ◽  
Golgi Network

Dual-color visualization of trans-Golgi network to plasma membrane traffic along microtubules in living cells

1999 ◽  
Vol 112 (1) ◽  
pp. 21-33 ◽  
Author(s):  
D. Toomre ◽  
P. Keller ◽  
J. White ◽  
J.C. Olivo ◽  
K. Simons
Keyword(s):  
Plasma Membrane ◽  
Protein Trafficking ◽  
Membrane Traffic ◽  
Living Cells ◽  
Tubular Structures ◽  
Trans Golgi Network ◽  
Vesicular Stomatitis ◽  
Golgi Network ◽  
Color Visualization

The mechanisms and carriers responsible for exocytic protein trafficking between the trans-Golgi network (TGN) and the plasma membrane remain unclear. To investigate the dynamics of TGN-to-plasma membrane traffic and role of the cytoskeleton in these processes we transfected cells with a GFP-fusion protein, vesicular stomatitis virus G protein tagged with GFP (VSVG3-GFP). After using temperature shifts to block VSVG3-GFP in the endoplasmic reticulum and subsequently accumulate it in the TGN, dynamics of TGN-to-plasma membrane transport were visualized in real time by confocal and video microscopy. Both small vesicles (<250 nm) and larger vesicular-tubular structures (>1.5 microm long) are used as transport containers (TCs). These TCs rapidly moved out of the Golgi along curvilinear paths with average speeds of approximately 0.7 micrometer/second. Automatic computer tracking objectively determined the dynamics of different carriers. Fission and fusion of TCs were observed, suggesting that these late exocytic processes are highly interactive. To directly determine the role of microtubules in post-Golgi traffic, rhodamine-tubulin was microinjected and both labeled cargo and microtubules were simultaneously visualized in living cells. These studies demonstrated that exocytic cargo moves along microtubule tracks and reveals that carriers are capable of switching between tracks.

scholarly journals Uni-directional ciliary membrane protein trafficking by a cytoplasmic retrograde IFT motor and ciliary ectosome shedding

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Muqing Cao ◽  
Jue Ning ◽  
Carmen I Hernandez-Lara ◽  
Olivier Belzile ◽  
Qian Wang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Protein Trafficking ◽  
Protein Composition ◽  
Cytoplasmic Dynein ◽  
Cytoplasmic Microtubule ◽  
Dynamic Regulation ◽  
Ciliary Membrane ◽  
Membrane Protein Trafficking

The role of the primary cilium in key signaling pathways depends on dynamic regulation of ciliary membrane protein composition, yet we know little about the motors or membrane events that regulate ciliary membrane protein trafficking in existing organelles. Recently, we showed that cilium-generated signaling in Chlamydomonas induced rapid, anterograde IFT-independent, cytoplasmic microtubule-dependent redistribution of the membrane polypeptide, SAG1-C65, from the plasma membrane to the periciliary region and the ciliary membrane. Here, we report that the retrograde IFT motor, cytoplasmic dynein 1b, is required in the cytoplasm for this rapid redistribution. Furthermore, signaling-induced trafficking of SAG1-C65 into cilia is unidirectional and the entire complement of cellular SAG1-C65 is shed during signaling and can be recovered in the form of ciliary ectosomes that retain signal-inducing activity. Thus, during signaling, cells regulate ciliary membrane protein composition through cytoplasmic action of the retrograde IFT motor and shedding of ciliary ectosomes.

scholarly journals Localization of TGN38 to the trans-Golgi network: involvement of a cytoplasmic tyrosine-containing sequence.

1993 ◽  
Vol 120 (5) ◽  
pp. 1123-1135 ◽  
Author(s):  
J S Humphrey ◽  
P J Peters ◽  
L C Yuan ◽  
J S Bonifacino
Keyword(s):  
Plasma Membrane ◽  
Amino Acid ◽  
Membrane Protein ◽  
Protein Localization ◽  
Chimeric Proteins ◽  
Plasma Membrane Protein ◽  
Intracellular Vesicles ◽  
Golgi Network ◽  
Amino Acid Segment ◽  
Cytoplasmic Determinants

Protein localization to the TGN was investigated by examining the subcellular distribution of chimeric proteins in which the cytoplasmic and/or transmembrane domains of the TGN protein, TGN38, were substituted for the analogous domains of the plasma membrane protein, Tac. Using immunofluorescence and immunoelectron microscopy, the COOH-terminal cytoplasmic domain of TGN38 was found to be sufficient for localization of the chimeric proteins to the TGN. Deletion analysis identified an 11-amino acid segment containing the critical sequence, YQRL, as being sufficient for TGN localization. TGN localization was abrogated by mutation of the tyrosine or leucine residues in this sequence to alanine, or of the arginine residue to aspartate. In addition to specifying TGN localization, the 11-amino acid segment was active as an internalization signal, although the property of internalization alone was insufficient to confer TGN localization. Overexpression of chimeric proteins containing TGN localization determinants resulted in their detection at the plasma membrane and in intracellular vesicles, and abolished detection of endogenous TGN38. These results suggest that discrete cytoplasmic determinants can mediate protein localization to the TGN, and reveal a novel role for tyrosine-based motifs in this process.

Versatile role of the yeast ubiquitin ligase Rsp5p in intracellular trafficking

2008 ◽  
Vol 36 (5) ◽  
pp. 791-796 ◽  
Author(s):  
Naima Belgareh-Touzé ◽  
Sébastien Léon ◽  
Zoi Erpapazoglou ◽  
Marta Stawiecka-Mirota ◽  
Danièle Urban-Grimal ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Ubiquitin Ligase ◽  
Protein Trafficking ◽  
Adaptor Proteins ◽  
Binding Domains ◽  
Independent Functions ◽  
Membrane Protein Trafficking ◽  
Ubiquitin Ligase E3

The ubiquitin ligase (E3) Rsp5p is the only member of the Nedd (neural-precursor-cell-expressed, developmentally down-regulated) 4 family of E3s present in yeast. Rsp5p has several proteasome-independent functions in membrane protein trafficking, including a role in the ubiquitination of most plasma membrane proteins, leading to their endocytosis. Rsp5p is also required for the ubiquitination of endosomal proteins, leading to their sorting to the internal vesicles of MVBs (multivesicular bodies). Rsp5p catalyses the attachment of non-conventional ubiquitin chains, linked through ubiquitin Lys-63, to some endocytic and MVB cargoes. This modification appears to be required for efficient sorting, possibly because these chains have a greater affinity for the ubiquitin-binding domains present within endocytic or MVB sorting complexes. The mechanisms involved in the recognition of plasma membrane and MVB substrates by Rsp5p remain unclear. A subset of Rsp5/Nedd4 substrates have a ‘PY motif’ and are recognized directly by the WW (Trp-Trp) domains of Rsp5p. Most Rsp5p substrates do not carry PY motifs, but some may depend on PY-containing proteins for their ubiquitination by Rsp5p, consistent with the latter's acting as specificity factors or adaptors. As in other ubiquitin-conjugating systems, these adaptors are also Rsp5p substrates and undergo ubiquitin-dependent trafficking. In the present review, we discuss recent examples illustrating the role of Rsp5p in membrane protein trafficking and providing new insights into the regulation of this E3 by adaptor proteins.

scholarly journals Endoplasmic Reticulum/Plasma Membrane Junctions Function as Membrane Protein Trafficking Hubs

2013 ◽  
Vol 104 (2) ◽  
pp. 619a
Author(s):  
Philip D. Fox ◽  
Christpher J. Haberkorn ◽  
Aubrey V. Weigel ◽  
Elizabeth J. Akin ◽  
Matthew J. Kennedy ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Membrane Protein ◽  
Protein Trafficking ◽  
Membrane Protein Trafficking
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