Membrane traffic and polarization of lipid domains during cytokinesis

2008 ◽  
Vol 36 (3) ◽  
pp. 395-399 ◽  
Author(s):  
Arnaud Echard
Keyword(s):  
Intracellular Transport ◽  
Membrane Traffic ◽  
Membrane Composition ◽  
Intercellular Bridge ◽  
Animal Cells ◽  
Lipid Domain ◽  
Complex Events ◽  
Cytoskeletal Elements ◽  
Membrane Sealing ◽  
Endocytic Pathways

Growing evidence indicates that membrane traffic plays a crucial role during the late post-furrowing steps of cytokinesis in animal cells. Indeed, both endocytosis and exocytosis contribute to stabilizing the intercellular bridge that connects the daughter cells and to the final abscission in diverse organisms. The need for several intracellular transport routes probably reflects the complex events that occur during the late cytokinesis steps such as local remodelling of the plasma membrane composition, removal of components required for earlier steps of cytokinesis and membrane sealing that leads to daughter cell separation. In this mini-review, I will focus on recent evidence showing that endocytic pathways, such as the Rab35-regulated recycling pathway, contribute to the establishment of a PtdIns(4,5)P2 lipid domain at the intercellular bridge which is involved in the localization of cytoskeletal elements essential for the late steps of cytokinesis. Possible cross-talk between Rab35 and other endocytic pathways involved in cytokinesis are also discussed.

scholarly journals Interactions of Lipid Droplets with the Intracellular Transport Machinery

2021 ◽  
Vol 22 (5) ◽  
pp. 2776
Author(s):  
Selma Yilmaz Dejgaard ◽  
John F. Presley
Keyword(s):  
Membrane Trafficking ◽  
Lipid Droplets ◽  
Intracellular Transport ◽  
Neutral Lipids ◽  
Small Gtpases ◽  
Lipid Phase ◽  
Intracellular Organelles ◽  
And Function ◽  
Lipid Phase Separation ◽  
Endocytic Pathways

Historically, studies of intracellular membrane trafficking have focused on the secretory and endocytic pathways and their major organelles. However, these pathways are also directly implicated in the biogenesis and function of other important intracellular organelles, the best studied of which are peroxisomes and lipid droplets. There is a large recent body of work on these organelles, which have resulted in the introduction of new paradigms regarding the roles of membrane trafficking organelles. In this review, we discuss the roles of membrane trafficking in the life cycle of lipid droplets. This includes the complementary roles of lipid phase separation and proteins in the biogenesis of lipid droplets from endoplasmic reticulum (ER) membranes, and the attachment of mature lipid droplets to membranes by lipidic bridges and by more conventional protein tethers. We also discuss the catabolism of neutral lipids, which in part results from the interaction of lipid droplets with cytosolic molecules, but with important roles for both macroautophagy and microautophagy. Finally, we address their eventual demise, which involves interactions with the autophagocytotic machinery. We pay particular attention to the roles of small GTPases, particularly Rab18, in these processes.

scholarly journals A Series of Tubes: The C. elegans Excretory Canal Cell as a Model for Tubule Development

2020 ◽  
Vol 8 (3) ◽  
pp. 17 ◽  
Author(s):  
Matthew Buechner ◽  
Zhe Yang ◽  
Hikmat Al-Hashimi
Keyword(s):  
Intracellular Transport ◽  
Renal Tubules ◽  
Genetic Screens ◽  
C Elegans ◽  
Brain Vasculature ◽  
Canal Cell ◽  
Mammalian Tissues ◽  
Cytoskeletal Elements ◽  
Excretory Canal

Formation and regulation of properly sized epithelial tubes is essential for multicellular life. The excretory canal cell of C. elegans provides a powerful model for investigating the integration of the cytoskeleton, intracellular transport, and organismal physiology to regulate the developmental processes of tube extension, lumen formation, and lumen diameter regulation in a narrow single cell. Multiple studies have provided new understanding of actin and intermediate filament cytoskeletal elements, vesicle transport, and the role of vacuolar ATPase in determining tube size. Most of the genes discovered have clear homologues in humans, with implications for understanding these processes in mammalian tissues such as Schwann cells, renal tubules, and brain vasculature. The results of several new genetic screens are described that provide a host of new targets for future studies in this informative structure.

Cytoskeletal elements and intracellular transport

2007 ◽  
Vol 101 (5) ◽  
pp. 1097-1108 ◽  
Author(s):  
Lakshmi Bhaskar ◽  
Vidya S. Krishnan ◽  
Raghava Varman Thampan
Keyword(s):  
Intracellular Transport ◽  
Cytoskeletal Elements

scholarly journals CCP1, a tubulin deglutamylase, increases survival of rodent spinal cord neurons following glutamate-induced excitotoxicity

2020 ◽  
Author(s):  
Yasmin H. Ramadan ◽  
Amanda Gu ◽  
Nicole Ross ◽  
Sara A. McEwan ◽  
Maureen M. Barr ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Intracellular Transport ◽  
Spinal Cord Injuries ◽  
Neuronal Injury ◽  
Post Translational Modification ◽  
Spinal Cord Neurons ◽  
C Elegans ◽  
Structural Support ◽  
Cytoskeletal Elements

AbstractMicrotubules (MTs) are cytoskeletal elements that provide structural support, establish morphology, and act as roadways for intracellular transport in cells. Neurons extend and must maintain long axons and dendrites to transmit information through the nervous system. Therefore, in neurons, the ability to independently regulate cytoskeletal stability and MT-based transport in different cellular compartments is essential. Post-translational modification of MTs is one mechanism by which neurons can regulate the cytoskeleton.The carboxypeptidase CCP1 negatively regulates post-translational glutamylation of MTs. We previously demonstrated that the CCP1 homolog in C. elegans is important for maintenance of cilia. In mammals, loss of CCP1, and the resulting hyperglutamylation of MTs, causes neurodegeneration. It has long been known that CCP1 expression is activated by neuronal injury; however, whether CCP1 plays a neuroprotective role after injury is unknown. Furthermore, it not yet clear whether CCP1 acts on ciliary MTs in spinal cord neurons.Using an in vitro model of excitotoxic neuronal injury coupled with shRNA-mediated knockdown of CCP1, we demonstrate that CCP1 protects neurons from excitotoxic death. Unexpectedly, excitotoxic injury reduced CCP1 expression in our system, and knockdown of CCP1 did not result in loss or shortening of cilia in cultured spinal cord neurons. Our results suggest that CCP1 acts on axonal and dendritic MTs to promote cytoskeletal rearrangements that support neuroregeneration and that enzymes responsible for glutamylation of MTs might be therapeutically targeted to prevent excitotoxic death after spinal cord injuries.

scholarly journals Endocytosis and the internalization of pathogenic organisms: focus on phosphoinositides

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 368
Author(s):  
Glenn F. W. Walpole ◽  
Sergio Grinstein
Keyword(s):  
Host Cell ◽  
Signaling Pathways ◽  
Molecular Mimicry ◽  
Current Knowledge ◽  
Membrane Traffic ◽  
Phosphoinositide Metabolism ◽  
Metabolic Advantage ◽  
Considerable Depth ◽  
Endocytic Pathways

Despite their comparatively low abundance in biological membranes, phosphoinositides are key to the regulation of a diverse array of signaling pathways and direct membrane traffic. The role of phosphoinositides in the initiation and progression of endocytic pathways has been studied in considerable depth. Recent advances have revealed that distinct phosphoinositide species feature prominently in clathrin-dependent and -independent endocytosis as well as in phagocytosis and macropinocytosis. Moreover, a variety of intracellular and cell-associated pathogens have developed strategies to commandeer host cell phosphoinositide metabolism to gain entry and/or metabolic advantage, thereby promoting their survival and proliferation. Here, we briefly survey the current knowledge on the involvement of phosphoinositides in endocytosis, phagocytosis, and macropinocytosis and highlight several examples of molecular mimicry employed by pathogens to either “hitch a ride” on endocytic pathways endogenous to the host or create an entry path of their own.

scholarly journals Aberrant Membrane Composition and Biophysical Properties Impair Erythrocyte Morphology and Functionality in Elliptocytosis

Biomolecules ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1120
Author(s):  
Hélène Pollet ◽  
Anne-Sophie Cloos ◽  
Amaury Stommen ◽  
Juliette Vanderroost ◽  
Louise Conrard ◽  
...  
Keyword(s):  
Cholesterol Content ◽  
Membrane Curvature ◽  
Acid Sphingomyelinase ◽  
Cholesterol Depletion ◽  
Membrane Composition ◽  
Biophysical Properties ◽  
Erythrocyte Morphology ◽  
Lipid Domain ◽  
Functional Consequences

Red blood cell (RBC) deformability is altered in inherited RBC disorders but the mechanism behind this is poorly understood. Here, we explored the molecular, biophysical, morphological, and functional consequences of α-spectrin mutations in a patient with hereditary elliptocytosis (pEl) almost exclusively expressing the Pro260 variant of SPTA1 and her mother (pElm), heterozygous for this mutation. At the molecular level, the pEI RBC proteome was globally preserved but spectrin density at cell edges was increased. Decreased phosphatidylserine vs. increased lysophosphatidylserine species, and enhanced lipid peroxidation, methemoglobin, and plasma acid sphingomyelinase (aSMase) activity were observed. At the biophysical level, although membrane transversal asymmetry was preserved, curvature at RBC edges and rigidity were increased. Lipid domains were altered for membrane:cytoskeleton anchorage, cholesterol content and response to Ca2+ exchange stimulation. At the morphological and functional levels, pEl RBCs exhibited reduced size and circularity, increased fragility and impaired membrane Ca2+ exchanges. The contribution of increased membrane curvature to the pEl phenotype was shown by mechanistic experiments in healthy RBCs upon lysophosphatidylserine membrane insertion. The role of lipid domain defects was proved by cholesterol depletion and aSMase inhibition in pEl. The data indicate that aberrant membrane content and biophysical properties alter pEl RBC morphology and functionality.

Rab11 polarization of theDrosophilaoocyte: a novel link between membrane trafficking, microtubule organization, andoskarmRNA localization and translation

Development ◽  
2002 ◽  
Vol 129 (2) ◽  
pp. 517-526 ◽  
Author(s):  
Gretchen Dollar ◽  
Eric Struckhoff ◽  
Jason Michaud ◽  
Robert S. Cohen
Keyword(s):  
Membrane Trafficking ◽  
Posterior Pole ◽  
Loss Of Function ◽  
Animal Cells ◽  
Partial Loss ◽  
Microtubule Organization ◽  
Microtubule Cytoskeleton ◽  
Translation Factors ◽  
Membrane Compartments ◽  
Endocytic Pathways

The Drosophila embryonic body plan is specified by asymmetries that arise in the oocyte during oogenesis. These asymmetries are apparent in the subcellular distribution of key mRNAs and proteins and in the organization of the microtubule cytoskeleton. We present evidence that the Drosophila oocyte also contains important asymmetries in its membrane trafficking pathways. Specifically, we show that α-adaptin and Rab11, which function critically in the endocytic pathways of all previously examined animal cells, are localized to neighboring compartments at the posterior pole of stage 8-10 oocytes. Rab11 and α-adaptin localization occurs in the absence of a polarized microtubule cytoskeleton, i.e. in grk null mutants, but is later reinforced and/or refined by Osk, the localization of which is microtubule dependent. Analyses of germline clones of a rab11 partial loss-of-function mutation reveal a requirement for Rab11 in endocytic recycling and in the organization of posterior membrane compartments. Such analyses also reveal a requirement for Rab11 in the organization of microtubule plus ends and osk mRNA localization and translation. We propose that microtubule plus ends and, possibly, translation factors for osk mRNA are anchored to posterior membrane compartments that are defined by Rab11-mediated trafficking and reinforced by Rab11-Osk interactions.

scholarly journals Fluorescent conjugates of brefeldin A selectively stain the endoplasmic reticulum and Golgi complex of living cells.

1995 ◽  
Vol 43 (9) ◽  
pp. 907-915 ◽  
Author(s):  
Y Deng ◽  
J R Bennink ◽  
H C Kang ◽  
R P Haugland ◽  
J W Yewdell
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Bilayers ◽  
Golgi Complex ◽  
Intracellular Transport ◽  
Brefeldin A ◽  
Living Cells ◽  
Vesicular Trafficking ◽  
Cellular Functions ◽  
Animal Cells ◽  
Specific Localization

The fungal metabolite brefeldin A (BFA) interferes with vesicular trafficking in most animal cells. To gain insight into the mechanism of BFA action, we esterified it to the fluorophore, boron dipyromethene difluoride (BODIPY). BODIPY-BEA localized predominantly in the endoplasmic reticulum (ER) and Golgi complex of viable cells and was extracted by detergent treatment, suggesting it interacts primarily with lipid bilayers. The localization of the conjugate is conferred by BFA, since free BODIPY or BODIPY esterified to cyclopentanol did not specifically localize to internal membranes. BODIPY-BFA exhibited a similar biological activity to BFA, but only when used at higher concentrations and after a delay. HPLC analysis revealed that over this period, cells converted BODIPY-BFA to species co-eluting with free BODIPY and BFA. Therefore, BODIPY-BFA is probably inactive until BFA is released by cellular esterases. The specific localization of BODIPY-BFA to the ER and Golgi complex suggests that BFA might exert its effects on vesicular trafficking by perturbing the lipid bilayer of its target organelles. Because BODIPY-BFA intensely stains the ER at concentrations that have no discernible effects on intracellular transport or other cellular functions, it should be useful for visualizing the ER in living cells.

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