scholarly journals The Recycling Endosome in Nerve Cell Development: One Rab to Rule Them All?

Author(s):  
Victoria Rozés-Salvador ◽  
Christian González-Billault ◽  
Cecilia Conde

Endocytic recycling is an intracellular process that returns internalized molecules back to the plasma membrane and plays crucial roles not only in the reuse of receptor molecules but also in the remodeling of the different components of this membrane. This process is required for a diversity of cellular events, including neuronal morphology acquisition and functional regulation, among others. The recycling endosome (RE) is a key vesicular component involved in endocytic recycling. Recycling back to the cell surface may occur with the participation of several different Rab proteins, which are master regulators of membrane/protein trafficking in nerve cells. The RE consists of a network of interconnected and functionally distinct tubular subdomains that originate from sorting endosomes and transport their cargoes along microtubule tracks, by fast or slow recycling pathways. Different populations of REs, particularly those formed by Rab11, Rab35, and Arf6, are associated with a myriad of signaling proteins. In this review, we discuss the cumulative evidence suggesting the existence of heterogeneous domains of REs, controlling different aspects of neurogenesis, with a particular focus on the commonalities and singularities of these REs and their contribution to nerve development and differentiation in several animal models.

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Michael G. Connor ◽  
Amanda R. Pulsifer ◽  
Donghoon Chung ◽  
Eric C. Rouchka ◽  
Brian K. Ceresa ◽  
...  

ABSTRACTYersinia pestishas evolved many strategies to evade the innate immune system. One of these strategies is the ability to survive within macrophages. Upon phagocytosis,Y. pestisprevents phagolysosome maturation and establishes a modified compartment termed theYersinia-containing vacuole (YCV).Y. pestisactively inhibits the acidification of this compartment, and eventually, the YCV transitions from a tight-fitting vacuole into a spacious replicative vacuole. The mechanisms to generate the YCV have not been defined. However, we hypothesized that YCV biogenesis requiresY. pestisinteractions with specific host factors to subvert normal vesicular trafficking. In order to identify these factors, we performed a genome-wide RNA interference (RNAi) screen to identify host factors required forY. pestissurvival in macrophages. This screen revealed that 71 host proteins are required for intracellular survival ofY. pestis. Of particular interest was the enrichment for genes involved in endosome recycling. Moreover, we demonstrated thatY. pestisactively recruits Rab4a and Rab11b to the YCV in a type three secretion system-independent manner, indicating remodeling of the YCV byY. pestisto resemble a recycling endosome. While recruitment of Rab4a was necessary to inhibit YCV acidification and lysosomal fusion early during infection, Rab11b appeared to contribute to later stages of YCV biogenesis. We also discovered thatY. pestisdisrupts global host endocytic recycling in macrophages, possibly through sequestration of Rab11b, and this process is required for bacterial replication. These data provide the first evidence thatY. pestistargets the host endocytic recycling pathway to avoid phagolysosomal maturation and generate the YCV.IMPORTANCEYersinia pestiscan infect and survive within macrophages. However, the mechanisms that the bacterium use to subvert killing by these phagocytes have not been defined. To provide a better understanding of these mechanisms, we used an RNAi approach to identify host factors required for intracellularY. pestissurvival. This approach revealed that the host endocytic recycling pathway is essential forY. pestisto avoid clearance by the macrophage. We further demonstrate thatY. pestisremodels the phagosome to resemble a recycling endosome, allowing the bacterium to avoid the normal phagolysosomal maturation pathway. Moreover, we show that infection withY. pestisdisrupts normal recycling in the macrophage and that disruption is required for bacterial replication. These findings provide the first evidence thatY. pestistargets the host endocytic recycling pathway in order to evade killing by macrophages.


2007 ◽  
Vol 35 (4) ◽  
pp. 683-685 ◽  
Author(s):  
S. Li ◽  
V.C. Duance ◽  
E.J. Blain

The cytoskeleton, which in most cell types, including the intervertebral disc described here, comprises microfilaments, microtubules and intermediate filaments, plays important functions in many fundamental cellular events, including cell division, motility, protein trafficking and secretion. The cytoskeleton is also critical for communication; for example, alterations to the architecture of the F-actin (filamentous actin) cytoskeletal networks can affect communication between the cells and the extracellular matrix, potentially compromising tissue homoeostasis. Although there are limited studies to date, this paper aims to review current knowledge on F-actin cytoskeletal element organization in intervertebral disc cells, how F-actin differs with pathology and its implications for mechanotransduction.


2016 ◽  
Vol 130 (20) ◽  
pp. 1781-1792 ◽  
Author(s):  
Motoko Takahashi ◽  
Yoshihiro Hasegawa ◽  
Congxiao Gao ◽  
Yoshio Kuroki ◽  
Naoyuki Taniguchi

Numerous signal-transduction-related molecules are secreted proteins or membrane proteins, and the mechanism by which these molecules are regulated by glycan chains is a very important issue for developing an understanding of the cellular events that transpire. This review covers the functional regulation of epidermal growth factor receptor (EGFR), ErbB3 and the transforming growth factor β (TGF-β) receptor by N-glycans. This review shows that the N-glycans play important roles in regulating protein conformation and interactions with carbohydrate recognition molecules. These results point to the possibility of a novel strategy for controlling cell signalling and developing novel glycan-based therapeutics.


2017 ◽  
Vol 216 (7) ◽  
pp. 2131-2150 ◽  
Author(s):  
William J. Monis ◽  
Victor Faundez ◽  
Gregory J. Pazour

Primary cilia perceive the extracellular environment through receptors localized in the ciliary membrane, but mechanisms directing specific proteins to this domain are poorly understood. To address this question, we knocked down proteins potentially important for ciliary membrane targeting and determined how this affects the ciliary trafficking of fibrocystin, polycystin-2, and smoothened. Our analysis showed that fibrocystin and polycystin-2 are dependent on IFT20, GMAP210, and the exocyst complex, while smoothened delivery is largely independent of these components. In addition, we found that polycystin-2, but not smoothened or fibrocystin, requires the biogenesis of lysosome-related organelles complex-1 (BLOC-1) for ciliary delivery. Consistent with the role of BLOC-1 in sorting from the endosome, we find that disrupting the recycling endosome reduces ciliary polycystin-2 and causes its accumulation in the recycling endosome. This is the first demonstration of a role for BLOC-1 in ciliary assembly and highlights the complexity of pathways taken to the cilium.


2016 ◽  
Vol 27 (23) ◽  
pp. 3746-3756 ◽  
Author(s):  
Adenrele M. Gleason ◽  
Ken C. Q. Nguyen ◽  
David H. Hall ◽  
Barth D. Grant

Syndapin/pascin-family F-BAR domain proteins bind directly to membrane lipids and are associated with actin dynamics at the plasma membrane. Previous reports also implicated mammalian syndapin 2 in endosome function during receptor recycling, but precise analysis of a putative recycling function for syndapin in mammalian systems is difficult because of its effects on the earlier step of endocytic uptake and potential redundancy among the three separate genes that encode mammalian syndapin isoforms. Here we analyze the endocytic transport function of the only Caenorhabditis elegans syndapin, SDPN-1. We find that SDPN-1 is a resident protein of the early and basolateral recycling endosomes in the C. elegans intestinal epithelium, and sdpn-1 deletion mutants display phenotypes indicating a block in basolateral recycling transport. sdpn-1 mutants accumulate abnormal endosomes positive for early endosome and recycling endosome markers that are normally separate, and such endosomes accumulate high levels of basolateral recycling cargo. Furthermore, we observed strong colocalization of endosomal SDPN-1 with the F-actin biosensor Lifeact and found that loss of SDPN-1 greatly reduced Lifeact accumulation on early endosomes. Taken together, our results provide strong evidence for an in vivo function of syndapin in endocytic recycling and suggest that syndapin promotes transport via endosomal fission.


2014 ◽  
Vol 369 (1633) ◽  
pp. 20130155 ◽  
Author(s):  
Andrew J. Irving ◽  
Jenni Harvey

The endocrine hormone leptin plays a key role in regulating food intake and body weight via its actions in the hypothalamus. However, leptin receptors are highly expressed in many extra-hypothalamic brain regions and evidence is growing that leptin influences many central processes including cognition. Indeed, recent studies indicate that leptin is a potential cognitive enhancer as it markedly facilitates the cellular events underlying hippocampal-dependent learning and memory, including effects on glutamate receptor trafficking, neuronal morphology and activity-dependent synaptic plasticity. However, the ability of leptin to regulate hippocampal synaptic function markedly declines with age and aberrant leptin function has been linked to neurodegenerative disorders such as Alzheimer's disease (AD). Here, we review the evidence supporting a cognitive enhancing role for the hormone leptin and discuss the therapeutic potential of using leptin-based agents to treat AD.


2000 ◽  
Vol 149 (4) ◽  
pp. 901-914 ◽  
Author(s):  
Birte Sönnichsen ◽  
Stefano De Renzis ◽  
Erik Nielsen ◽  
Jens Rietdorf ◽  
Marino Zerial

Two endosome populations involved in recycling of membranes and receptors to the plasma membrane have been described, the early and the recycling endosome. However, this distinction is mainly based on the flow of cargo molecules and the spatial distribution of these membranes within the cell. To get insights into the membrane organization of the recycling pathway, we have studied Rab4, Rab5, and Rab11, three regulatory components of the transport machinery. Following transferrin as cargo molecule and GFP-tagged Rab proteins we could show that cargo moves through distinct domains on endosomes. These domains are occupied by different Rab proteins, revealing compartmentalization within the same continuous membrane. Endosomes are comprised of multiple combinations of Rab4, Rab5, and Rab11 domains that are dynamic but do not significantly intermix over time. Three major populations were observed: one that contains only Rab5, a second with Rab4 and Rab5, and a third containing Rab4 and Rab11. These membrane domains display differential pharmacological sensitivity, reflecting their biochemical and functional diversity. We propose that endosomes are organized as a mosaic of different Rab domains created through the recruitment of specific effector proteins, which cooperatively act to generate a restricted environment on the membrane.


2020 ◽  
Author(s):  
Marina Ikeda ◽  
Tadashi Watanabe ◽  
Akihiro Ito ◽  
Masahiro Fujimuro

Herpes simplex virus 1 (HSV-1) is a human DNA virus that causes cold sores, keratitis, meningitis, and encephalitis. Ubiquitination is a post-translational protein modification essential for regulation of cellular events, such as proteasomal degradation, signal transduction, and protein trafficking. The process is also involved in events for establishing viral infection and replication. The first step in ubiquitination involves ubiquitin (Ub) binding with Ub-activating enzyme (E1, also termed UBE1) via a thioester linkage. Our results show that HSV-1 infection alters protein ubiquitination pattern in host cells, as evidenced by MS spectra and co-immunoprecipitation assays. HSV-1 induced ubiquitination of UBE1a isoform via an isopeptide bond with Lys604. Moreover, we show that ubiquitination of K604 in UBE1a enhances UBE1a activity; that is, the activity of ubiquitin-transfer to E2 enzyme. Subsequently, we investigated the functional role of UBE1a and ubiquitination of K604 in UBE1a. We found that UBE1-knockdown increased HSV-1 DNA replication and viral production. Further, overexpression of UBE1a, but not a UBE1a K604A mutant, suppressed viral replication. Furthermore, we found that UBE1a and ubiquitination at K604 in UBE1a retarded expression of HSV-1 major capsid protein, ICP5. Our findings show that UBE1a functions as an antiviral factor that becomes activated upon ubiquitination at Lys604.


2008 ◽  
Vol 19 (10) ◽  
pp. 4224-4237 ◽  
Author(s):  
Hiroki Inoue ◽  
Vi Luan Ha ◽  
Rytis Prekeris ◽  
Paul A. Randazzo

ADP-ribosylation factors (Arfs) and Arf GTPase-activating proteins (GAPs) are key regulators of membrane trafficking and the actin cytoskeleton. The Arf GAP ASAP1 contains an N-terminal BAR domain, which can induce membrane tubulation. Here, we report that the BAR domain of ASAP1 can also function as a protein binding site. Two-hybrid screening identified FIP3, which is a putative Arf6- and Rab11-effector, as a candidate ASAP1 BAR domain-binding protein. Both coimmunoprecipitation and in vitro pulldown assays confirmed that ASAP1 directly binds to FIP3 through its BAR domain. ASAP1 formed a ternary complex with Rab11 through FIP3. FIP3 binding to the BAR domain stimulated ASAP1 GAP activity against Arf1, but not Arf6. ASAP1 colocalized with FIP3 in the pericentrosomal endocytic recycling compartment. Depletion of ASAP1 or FIP3 by small interfering RNA changed the localization of transferrin receptor, which is a marker of the recycling endosome, in HeLa cells. The depletion also altered the trafficking of endocytosed transferrin. These results support the conclusion that ASAP1, like FIP3, functions as a component of the endocytic recycling compartment.


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