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Rab Endosomes

David Novo, Nikki Heath, Louise Mitchell, Giuseppina Caligiuri, Amanda MacFarlane, Dide Reijmer, Laura Charlton, John Knight, Monika Calka, Ewan McGhee, Emmanuel Dornier, David Sumpton, Susan Mason, Arnaud Echard, Kerstin Klinkert, Judith Secklehner, Flore Kruiswijk, Karen Vousden, Iain R Macpherson, Karen Blyth, Peter Bailey, Huabing Yin, Leo M Carlin, Jennifer Morton, Sara Zanivan, Jim C Norman
Mutant p53s (mutp53) increase cancer invasiveness by upregulating Rab-coupling protein (RCP) and diacylglycerol kinase-α (DGKα)-dependent endosomal recycling. Here we report that mutp53-expressing tumour cells produce exosomes that mediate intercellular transfer of mutp53's invasive/migratory gain-of-function by increasing RCP-dependent integrin recycling in other tumour cells. This process depends on mutp53's ability to control production of the sialomucin, podocalyxin, and activity of the Rab35 GTPase which interacts with podocalyxin to influence its sorting to exosomes...
November 29, 2018: Nature Communications
So Morishita, Naoyuki Wada, Mitsunori Fukuda, Takeshi Nakamura
Macropinocytosis is a nonspecific bulk uptake of extracellular fluid. During endosome maturation, the Rab5-to-Rab7 switch machinery executes the conversion from early to late endosomes. However, how the Rab switch works during macropinosome maturation remains unclear. Here, we elucidate the Rab switch machinery in macropinosome maturation using FRET imaging. Rab5 is activated and concurrently recruited to macropinosomes during ruffle closure. ALS2 depletion abolishes transient Rab5 activation on macropinosomes, while ALS2 is recruited to macropinosomes simultaneously with Rab5 activation...
November 28, 2018: FEBS Letters
Gregory Artiushin, Shirley L Zhang, Hervé Tricoire, Amita Sehgal
Glia are important modulators of neural activity, yet few studies link glia to sleep regulation. We find that blocking activity of the endocytosis protein, dynamin, in adult Drosophila glia increases sleep and enhances sleep need, manifest as resistance to sleep deprivation. Surface glia comprising the fly equivalent of the blood-brain barrier (BBB) mediate the effect of dynamin on sleep. Blocking dynamin in the surface glia causes ultrastructural changes, albeit without compromising the integrity of the barrier...
November 26, 2018: ELife
Ping Li, Yong-Hong Wu, Yan-Ting Zhu, Man-Xiang Li, Hong-Hong Pei
Lipopolysaccharide (LPS) induces macrophage/monocyte activation and pro-inflammatory cytokines production by activating Toll-like receptor 4 (TLR-4) signaling. Rab GTPase 21 (Rab21) is a member of the Rab GTPase subfamily. In the present study, we show that LPS induced TLR4 and Rab21 association and endosomal translocation in murine bone marrow-derived macrophages (BMDMs) and primary human peripheral blood mononuclear cells (PBMCs). In BMDMs, shRNA-mediated stable knockdown of Rab21 inhibited LPS-induced expression and production of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α)...
November 21, 2018: Biochemical and Biophysical Research Communications
Yoshihiko Kuchitsu, Mitsunori Fukuda
Rab7 (or Ypt7 in yeast) is one of the well-characterized members of the Rab family small GTPases, which serve as master regulators of membrane trafficking in eukaryotes. It localizes to late endosomes and lysosomes and has multiple functions in the autophagic pathway as well as in the endocytic pathway. Because Rab7/Ypt7 has previously been shown to regulate the autophagosome-lysosome fusion step in yeast and fruit flies (i.e., autophagosome accumulation has been observed in both Ypt7-knockout [KO] yeast and Rab7-knockdown fruit flies), it is widely assumed that Rab7 regulates the autophagosome-lysosome fusion step in mammals...
November 19, 2018: Cells
Caitlin Morris, Olivia K Foster, Simran Handa, Kimberly Peloza, Laura Voss, Hannah Somhegyi, Youli Jian, My Van Vo, Marie Harp, Fiona M Rambo, Chonglin Yang, Greg J Hermann
Cell type-specific modifications of conventional endosomal trafficking pathways lead to the formation of lysosome-related organelles (LROs). C. elegans gut granules are intestinally restricted LROs that coexist with conventional degradative lysosomes. The formation of gut granules requires the Rab32 family member GLO-1. We show that the loss of glo-1 leads to the mistrafficking of gut granule proteins but does not significantly alter conventional endolysosome biogenesis. GLO-3 directly binds to CCZ-1 and they both function to promote the gut granule association of GLO-1, strongly suggesting that together, GLO-3 and CCZ-1 activate GLO-1...
November 12, 2018: PLoS Genetics
Saurabh Shakya, Prerna Sharma, Anshul Milap Bhatt, Riddhi Atul Jani, Cédric Delevoye, Subba Rao Gangi Setty
Recycling endosomes (REs) are transient endosomal tubular intermediates of early/sorting endosomes (E/SEs) that function in cargo recycling to the cell surface and deliver the cell type-specific cargo to lysosome-related organelles such as melanosomes in melanocytes. However, the mechanism of RE biogenesis is largely unknown. In this study, by using an endosomal Rab-specific RNAi screen, we identified Rab22A as a critical player during RE biogenesis. Rab22A-knockdown results in reduced RE dynamics and concurrent cargo accumulation in the E/SEs or lysosomes...
November 7, 2018: EMBO Reports
Xue Chun Yao, Xue Xue, Hao Tian Zhang, Ming Ming Zhu, Xiao Wei Yang, Chun Fu Wu, Jing Yu Yang
Amyloid accumulation in the brain is the major pathological hallmark of Alzheimer's disease (AD). Amyloid beta (Aβ) is cleared by the endosomal-autophagy-lysosomal system, which is impaired in AD pathogenesis by an unknown mechanism. Pseudoginsenoside-F11 (PF11), an ocotillol-type ginsenoside, has been demonstrated to decrease the level of Aβ in APP/PS1 mouse brain and to protect neurons by inhibiting the activation of microglia in vitro. The present study showed that PF11 was capable of increasing the uptake and degradation of oligomeric Aβ in cultured microglia...
October 29, 2018: Traffic
Juan Carlos Martínez-Morales, M Teresa Romero-Ávila, Guadalupe Reyes-Cruz, J Adolfo García-Sáinz
Sphingosine 1-phosphate and FTY720-phosphate increased intracellular calcium in cells expressing S1P1 mCherry-tagged receptors; the synthetic agonist was considerably less potent. Activation of protein kinase C by phorbol myristate acetate blocked these effects. The three agents induced receptor phosphorylation and internalization, with the action of FTY720-phosphate being more intense. S1P1 receptor-Rab protein (Green Fluorescent Protein-tagged) interaction was studied using Förster Resonance Energy Transfer...
October 26, 2018: Bioscience Reports
Jia Wu, Dandan Cheng, Li Liu, Zhengbing Lv, Kuancheng Liu
Glucose transport into skeletal muscle is mediated by the principal glucose transporter protein, GLUT4, which can be transported from intracellular vesicles to the cytoplasmic membrane, and the translocation of GLUT4 vesicles requires a variety of Rab proteins. Previously we reported a new type of TBC1D15 from C. plagiosum with Rab-GAP activity for Rab7. Here we reported that TBC1D15 regulated glucose uptake by affecting the translocation of GLUT4 through late endosomal pathway. When TBC1D15 was knocked out by CRISPR/Cas9, a significant reduction in 2-NBDG uptake was observed, and the total amount of GLUT4 was significantly reduced in TBC1D15-/- cells compared to that in WT cells...
January 30, 2019: Gene
A C Kokotos, J Peltier, E C Davenport, M Trost, M A Cousin
Activity-dependent bulk endocytosis (ADBE) is the dominant mode of synaptic vesicle endocytosis during high-frequency stimulation, suggesting it should play key roles in neurotransmission during periods of intense neuronal activity. However, efforts in elucidating the physiological role of ADBE have been hampered by the lack of identified molecules which are unique to this endocytosis mode. To address this, we performed proteomic analysis on purified bulk endosomes, which are a key organelle in ADBE. Bulk endosomes were enriched via two independent approaches, a classical subcellular fractionation method and isolation via magnetic nanoparticles...
October 23, 2018: Proceedings of the National Academy of Sciences of the United States of America
Nan Zhang, Xu Wang, Verena Gobel, Xichen Zhang
RAB-11/Rab11 is an endosomal GTPase with conserved roles in directional trafficking and apical domain formation in polarized epithelial cells. From a yeast two-hybrid screen using full-length C. elegans RAB-11 as bait, we identified LEC-5 as a novel binding protein for RAB-11. LEC-5 is an ortholog of mammalian Galectin-9 which associates with glycosphingolipids and is implicated in apical cargo sorting. We further confirmed the interaction between RAB-11 and LEC-5 via GST-pull down, co-immunoprecipitation and bimolecular fluorescence complementation...
October 28, 2018: Biochemical and Biophysical Research Communications
Todd Bradley, Dimitra Peppa, Isabela Pedroza-Pacheco, Dapeng Li, Derek W Cain, Ricardo Henao, Vaishnavi Venkat, Bhavna Hora, Yue Chen, Nathan A Vandergrift, R Glenn Overman, R Whitney Edwards, Chris W Woods, Georgia D Tomaras, Guido Ferrari, Geoffrey S Ginsburg, Mark Connors, Myron S Cohen, M Anthony Moody, Persephone Borrow, Barton F Haynes
HIV-1 broadly neutralizing antibodies (bnAbs) are difficult to induce with vaccines but are generated in ∼50% of HIV-1-infected individuals. Understanding the molecular mechanisms of host control of bnAb induction is critical to vaccine design. Here, we performed a transcriptome analysis of blood mononuclear cells from 47 HIV-1-infected individuals who made bnAbs and 46 HIV-1-infected individuals who did not and identified in bnAb individuals upregulation of RAB11FIP5, encoding a Rab effector protein associated with recycling endosomes...
October 4, 2018: Cell
Giuseppina Grieco, Virginie Janssens, Héloïse P Gaide Chevronnay, Francisca N'Kuli, Patrick Van Der Smissen, Tongsong Wang, Jingdong Shan, Seppo Vainio, Benoit Bilanges, François Jouret, Bart Vanhaesebroeck, Christophe E Pierreux, Pierre J Courtoy
Kidney proximal tubular cells (PTCs) are highly specialized for ultrafiltrate reabsorption and serve as paradigm of apical epithelial differentiation. Vps34/PI3-kinase type III (PI3KC3) regulates endosomal dynamics, macroautophagy and lysosomal function. However, its in vivo role in PTCs has not been evaluated. Conditional deletion of Vps34/PI3KC3 in PTCs by Pax8-Cre resulted in early (P7) PTC dysfunction, manifested by Fanconi-like syndrome, followed by kidney failure (P14) and death. By confocal microscopy, Vps34∆/∆ PTCs showed preserved apico-basal specification (brush border, NHERF-1 versus Na+ /K+ -ATPase, ankyrin-G) but basal redistribution of late-endosomes/lysosomes (LAMP-1) and mis-localization to lysosomes of apical recycling endocytic receptors (megalin, cubilin) and apical non-recycling solute carriers (NaPi-IIa, SGLT-2)...
September 20, 2018: Scientific Reports
Qi Yan, Mingqun Lin, Weiyan Huang, Omid Teymournejad, Jennifer M Johnson, Franklin A Hays, Zhimin Liang, Guangpu Li, Yasuko Rikihisa
Ehrlichia chaffeensis , an obligatory intracellular bacterium, infects monocytes/macrophages by sequestering a regulator of endosomal traffic, the small GTPase RAB5, on its membrane-bound inclusions to avoid routing to host-cell phagolysosomes. How RAB5 is sequestered on ehrlichial inclusions is poorly understood, however. We found that native Ehrlichia translocated factor-2 (Etf-2), a previously predicted effector of the Ehrlichia type IV secretion system, and recombinant Etf-2 (cloned into the Ehrlichia genome) are secreted into the host-cell cytoplasm and localize to ehrlichial inclusions...
September 18, 2018: Proceedings of the National Academy of Sciences of the United States of America
Takashi Nozawa
Autophagy acts as an intracellular host defense system against invading pathogenic microorganisms such as Group A Streptococcus (GAS). Autophagy is a membrane-mediated degradation system that is regulated by intracellular membrane trafficking regulators, including small GTPase Rab proteins. Here, we revealed Rab GTPase network that regulate autophagosome formation against GAS. A unique set of Rab GTPases coordinates autophagy to enable to form huge autophagosomes surrounding GAS by linking recycling endosomes and trans Golgi-network...
2018: Nihon Saikingaku Zasshi. Japanese Journal of Bacteriology
Ryan Haley, Ying Wang, Zheng Zhou
In metazoans, apoptotic cells are swiftly engulfed by phagocytes and degraded inside phagosomes. Multiple small GTPases in the Rab family are known to function in phagosome maturation by regulating vesicle trafficking. We discovered rab-35 as a new gene important for apoptotic cell clearance from a genetic screen targeting putative Rab GTPases in Caenorhabditis elegans. We further identified TBC-10 as a putative GTPase-activating protein (GAP), and FLCN-1 and RME-4 as two putative Guanine Nucleotide Exchange Factors (GEFs), for RAB-35...
August 2018: PLoS Genetics
Marita Borg Distefano, Linda Hofstad Haugen, Yan Wang, Harmonie Perdreau-Dahl, Ingrid Kjos, Da Jia, Jens Preben Morth, Jacques Neefjes, Oddmund Bakke, Cinzia Progida
Rab GTPases are key regulators of intracellular trafficking, and cycle between a GTP-bound active state and a GDP-bound inactive state. This cycle is regulated by guanine-nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Several efforts have been made in connecting the correct GEFs and GAPs to their specific Rab. Here, we aimed to identify GAPs for Rab7b, the small GTPase involved in transport from late endosomes to the trans-Golgi. An siRNA screen targeting proteins containing TBC domains critical for Rab GAPs was performed and coupled to a phenotypic read-out that visualized the distribution of Rab7b...
September 3, 2018: Journal of Cell Science
Carla Brillada, Jiameng Zheng, Falco Krüger, Eliezer Rovira-Diaz, Jana Christin Askani, Karin Schumacher, Marcela Rojas-Pierce
The vacuole is an essential organelle in plant cells, and its dynamic nature is important for plant growth and development. Homotypic membrane fusion is required for vacuole biogenesis, pollen germination, stomata opening, and gravity perception. Known components of the vacuole fusion machinery in eukaryotes include SNARE proteins, Rab GTPases, phosphoinositides, and the homotypic fusion and vacuolar protein sorting (HOPS) tethering complex. HOPS function is not well characterized in plants, but roles in embryogenesis and pollen tube elongation have been reported...
August 28, 2018: Proceedings of the National Academy of Sciences of the United States of America
Noga Budick-Harmelin, Marta Miaczynska
Maintenance of physiologic cellular functions and homeostasis requires highly coordinated interactions between different cellular compartments. In this regard, the endocytic system, which plays a key role in cargo internalization and trafficking within the cell, participates in upkeep of intracellular dynamics, while communicating with multiple organelles. This chapter will discuss the function of endosomes from a standpoint of cellular integration. We will present examples of different types of interactions between endosomes and other cellular compartments, such as the endoplasmic reticulum (ER), mitochondria, the plasma membrane (PM), and the nuclear envelope...
2018: Progress in Molecular and Subcellular Biology
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