Faculty Opinions recommendation of MTV proteins unveil ER- and microtubule-associated compartments in the plant vacuolar trafficking pathway.

2020 ◽  
Author(s):  
Diane Bassham
Keyword(s):  
Trafficking Pathway ◽  
Vacuolar Trafficking

scholarly journals MTV proteins unveil ER- and microtubule-associated compartments in the plant vacuolar trafficking pathway

2020 ◽  
Vol 117 (18) ◽  
pp. 9884-9895 ◽  
Author(s):  
María Otilia Delgadillo ◽  
Guillermo Ruano ◽  
Jan Zouhar ◽  
Michael Sauer ◽  
Jinbo Shen ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Motor Domain ◽  
Multivesicular Bodies ◽  
Trafficking Pathway ◽  
Vacuolar Transport ◽  
Dependent Transport ◽  
Golgi Network ◽  
Garp Complex ◽  
Vacuolar Trafficking

The factors and mechanisms involved in vacuolar transport in plants, and in particular those directing vesicles to their target endomembrane compartment, remain largely unknown. To identify components of the vacuolar trafficking machinery, we searched for Arabidopsis modified transport to the vacuole (mtv) mutants that abnormally secrete the synthetic vacuolar cargo VAC2. We report here on the identification of 17 mtv mutations, corresponding to mutant alleles of MTV2/VSR4, MTV3/PTEN2A MTV7/EREL1, MTV8/ARFC1, MTV9/PUF2, MTV10/VPS3, MTV11/VPS15, MTV12/GRV2, MTV14/GFS10, MTV15/BET11, MTV16/VPS51, MTV17/VPS54, and MTV18/VSR1. Eight of the MTV proteins localize at the interface between the trans-Golgi network (TGN) and the multivesicular bodies (MVBs), supporting that the trafficking step between these compartments is essential for segregating vacuolar proteins from those destined for secretion. Importantly, the GARP tethering complex subunits MTV16/VPS51 and MTV17/VPS54 were found at endoplasmic reticulum (ER)- and microtubule-associated compartments (EMACs). Moreover, MTV16/VPS51 interacts with the motor domain of kinesins, suggesting that, in addition to tethering vesicles, the GARP complex may regulate the motors that transport them. Our findings unveil a previously uncharacterized compartment of the plant vacuolar trafficking pathway and support a role for microtubules and kinesins in GARP-dependent transport of soluble vacuolar cargo in plants.

scholarly journals Cargo sorting zones in the trans-Golgi network visualized by super-resolution confocal live imaging microscopy in plants

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yutaro Shimizu ◽  
Junpei Takagi ◽  
Emi Ito ◽  
Yoko Ito ◽  
Kazuo Ebine ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
High Speed ◽  
Super Resolution ◽  
Adaptor Protein ◽  
Transport Proteins ◽  
3D Localization ◽  
Golgi Network ◽  
Distinct Distribution ◽  
Vacuolar Trafficking ◽  
Cargo Sorting

AbstractThe trans-Golgi network (TGN) has been known as a key platform to sort and transport proteins to their final destinations in post-Golgi membrane trafficking. However, how the TGN sorts proteins with different destinies still remains elusive. Here, we examined 3D localization and 4D dynamics of TGN-localized proteins of Arabidopsis thaliana that are involved in either secretory or vacuolar trafficking from the TGN, by a multicolor high-speed and high-resolution spinning-disk confocal microscopy approach that we developed. We demonstrate that TGN-localized proteins exhibit spatially and temporally distinct distribution. VAMP721 (R-SNARE), AP (adaptor protein complex)−1, and clathrin which are involved in secretory trafficking compose an exclusive subregion, whereas VAMP727 (R-SNARE) and AP-4 involved in vacuolar trafficking compose another subregion on the same TGN. Based on these findings, we propose that the single TGN has at least two subregions, or “zones”, responsible for distinct cargo sorting: the secretory-trafficking zone and the vacuolar-trafficking zone.

scholarly journals Rha1, an Arabidopsis Rab5 Homolog, Plays a Critical Role in the Vacuolar Trafficking of Soluble Cargo Proteins

2003 ◽  
Vol 15 (5) ◽  
pp. 1057-1070 ◽  
Author(s):  
Eun Ju Sohn ◽  
Eol Sun Kim ◽  
Min Zhao ◽  
Soo Jin Kim ◽  
Hyeran Kim ◽  
...  
Keyword(s):  
Critical Role ◽  
Cargo Proteins ◽  
Vacuolar Trafficking

scholarly journals Overexpression of a Vesicle Trafficking Gene, OsRab7, Enhances Salt Tolerance in Rice

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaojue Peng ◽  
Xia Ding ◽  
Tianfang Chang ◽  
Zhoulong Wang ◽  
Rong Liu ◽  
...  
Keyword(s):  
Salt Tolerance ◽  
Transgenic Rice ◽  
Agricultural Production ◽  
Vesicle Trafficking ◽  
Yeast Cells ◽  
Root Tip ◽  
Over Expression ◽  
Crop Tolerance ◽  
Vacuolar Trafficking ◽  
Main Factor

High soils salinity is a main factor affecting agricultural production. Studying the function of salt-tolerance-related genes is essential to enhance crop tolerance to stress.Rab7is a small GTP-binding protein that is distributed widely among eukaryotes. Endocytic trafficking mediated byRab7plays an important role in animal and yeast cells, but the current understanding ofRab7in plants is still very limited. Herein, we isolated a vesicle trafficking gene,OsRab7, from rice. Transgenic rice over-expressingOsRab7exhibited enhanced seedling growth and increased proline content under salt-treated conditions. Moreover, an increased number of vesicles was observed in the root tip ofOsRab7transgenic rice. TheOsRab7over-expression plants showed enhanced tolerance to salt stress, suggesting that vacuolar trafficking is important for salt tolerance in plants.

scholarly journals Salmonella SipA mimics a cognate SNARE for host Syntaxin8 to promote fusion with early endosomes

2018 ◽  
Vol 217 (12) ◽  
pp. 4199-4214 ◽  
Author(s):  
Pawan Kishor Singh ◽  
Anjali Kapoor ◽  
Richa Madan Lomash ◽  
Kamal Kumar ◽  
Sukrut C. Kamerkar ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Enteric Fever ◽  
Caspase 3 ◽  
Arginine Residue ◽  
Terminal Domain ◽  
Trafficking Pathway ◽  
Early Endosomes ◽  
N Terminus ◽  
Snare Motif ◽  
Salmonella Survival

SipA is a major effector of Salmonella, which causes gastroenteritis and enteric fever. Caspase-3 cleaves SipA into two domains: the C-terminal domain regulates actin polymerization, whereas the function of the N terminus is unknown. We show that the cleaved SipA N terminus binds and recruits host Syntaxin8 (Syn8) to Salmonella-containing vacuoles (SCVs). The SipA N terminus contains a SNARE motif with a conserved arginine residue like mammalian R-SNAREs. SipAR204Q and SipA1–435R204Q do not bind Syn8, demonstrating that SipA mimics a cognate R-SNARE for Syn8. Consequently, Salmonella lacking SipA or that express the SipA1–435R204Q SNARE mutant are unable to recruit Syn8 to SCVs. Finally, we show that SipA mimicking an R-SNARE recruits Syn8, Syn13, and Syn7 to the SCV and promotes its fusion with early endosomes to potentially arrest its maturation. Our results reveal that SipA functionally substitutes endogenous SNAREs in order to hijack the host trafficking pathway and promote Salmonella survival.

scholarly journals The human B12 trafficking protein CblC processes nitrocobalamin

2020 ◽  
Vol 295 (28) ◽  
pp. 9630-9640 ◽  
Author(s):  
Romila Mascarenhas ◽  
Zhu Li ◽  
Carmen Gherasim ◽  
Markus Ruetz ◽  
Ruma Banerjee
Keyword(s):  
Nitrite Reductase ◽  
Reductase Activity ◽  
Methylmalonic Aciduria ◽  
Axial Ligand ◽  
Vitamin B ◽  
Early Step ◽  
Trafficking Pathway ◽  
Nitrite Reductase Activity ◽  
Futile Cycling ◽  
Thiol Oxidase

In humans, cobalamin or vitamin B12 is delivered to two target enzymes via a complex intracellular trafficking pathway comprising transporters and chaperones. CblC (or MMACHC) is a processing chaperone that catalyzes an early step in this trafficking pathway. CblC removes the upper axial ligand of cobalamin derivatives, forming an intermediate in the pathway that is subsequently converted to the active cofactor derivatives. Mutations in the cblC gene lead to methylmalonic aciduria and homocystinuria. Here, we report that nitrosylcobalamin (NOCbl), which was developed as an antiproliferative reagent, and is purported to cause cell death by virtue of releasing nitric oxide, is highly unstable in air and is rapidly oxidized to nitrocobalamin (NO2Cbl). We demonstrate that CblC catalyzes the GSH-dependent denitration of NO2Cbl forming 5-coordinate cob(II)alamin, which had one of two fates. It could be oxidized to aquo-cob(III)alamin or enter a futile thiol oxidase cycle forming GSH disulfide. Arg-161 in the active site of CblC suppressed the NO2Cbl-dependent thiol oxidase activity, whereas the disease-associated R161G variant stabilized cob(II)alamin and promoted futile cycling. We also report that CblC exhibits nitrite reductase activity, converting cob(I)alamin and nitrite to NOCbl. Finally, the denitration activity of CblC supported cell proliferation in the presence of NO2Cbl, which can serve as a cobalamin source. The newly described nitrite reductase and denitration activities of CblC extend its catalytic versatility, adding to its known decyanation and dealkylation activities. In summary, upon exposure to air, NOCbl is rapidly converted to NO2Cbl, which is a substrate for the B12 trafficking enzyme CblC.

scholarly journals Retromer has a selective function in cargo sorting via endosome transport carriers

2018 ◽  
Vol 218 (2) ◽  
pp. 615-631 ◽  
Author(s):  
Yi Cui ◽  
Julian M. Carosi ◽  
Zhe Yang ◽  
Nicholas Ariotti ◽  
Markus C. Kerr ◽  
...  
Keyword(s):  
Vesicular Trafficking ◽  
Lysosomal Hydrolases ◽  
Cell Level ◽  
Ultrastructural Alteration ◽  
Membrane Protein Complex ◽  
Lysosomal Function ◽  
Trafficking Pathway ◽  
Peripheral Membrane Protein ◽  
And Function ◽  
Proteolytic Capacity

Retromer is a peripheral membrane protein complex that coordinates multiple vesicular trafficking events within the endolysosomal system. Here, we demonstrate that retromer is required for the maintenance of normal lysosomal morphology and function. The knockout of retromer subunit Vps35 causes an ultrastructural alteration in lysosomal structure and aberrant lysosome function, leading to impaired autophagy. At the whole-cell level, knockout of retromer Vps35 subunit reduces lysosomal proteolytic capacity as a consequence of the improper processing of lysosomal hydrolases, which is dependent on the trafficking of the cation-independent mannose 6-phosphate receptor (CI-M6PR). Incorporation of CI-M6PR into endosome transport carriers via a retromer-dependent process is restricted to those tethered by GCC88 but not golgin-97 or golgin-245. Finally, we show that this retromer-dependent retrograde cargo trafficking pathway requires SNX3, but not other retromer-associated cargo binding proteins, such as SNX27 or SNX-BAR proteins. Therefore, retromer does contribute to the retrograde trafficking of CI-M6PR required for maturation of lysosomal hydrolases and lysosomal function.

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