Targeting to Lysosomes in Mammalian Cells: The Biosynthetic and Endocytic Pathways

2007 ◽  
pp. 339-362
Author(s):  
Ann H. Erickson ◽  
Jeffrey P. Bocock
Keyword(s):  
Mammalian Cells ◽  
Endocytic Pathways

scholarly journals EEA1, a Tethering Protein of the Early Sorting Endosome, Shows a Polarized Distribution in Hippocampal Neurons, Epithelial Cells, and Fibroblasts

2000 ◽  
Vol 11 (8) ◽  
pp. 2657-2671 ◽  
Author(s):  
Jean M. Wilson ◽  
Meltsje de Hoop ◽  
Natasha Zorzi ◽  
Ban-Hock Toh ◽  
Carlos G. Dotti ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Mammalian Cells ◽  
Hippocampal Neurons ◽  
Cell Types ◽  
Early Endosomes ◽  
Filamentous Material ◽  
Endocytic Vesicles ◽  
Fibroblastic Cells ◽  
Darby Canine Kidney ◽  
Endocytic Pathways

EEA1 is an early endosomal Rab5 effector protein that has been implicated in the docking of incoming endocytic vesicles before fusion with early endosomes. Because of the presence of complex endosomal pathways in polarized and nonpolarized cells, we have examined the distribution of EEA1 in diverse cell types. Ultrastructural analysis demonstrates that EEA1 is present on a subdomain of the early sorting endosome but not on clathrin-coated vesicles, consistent with a role in providing directionality to early endosomal fusion. Furthermore, EEA1 is associated with filamentous material that extends from the cytoplasmic surface of the endosomal domain, which is also consistent with a tethering/docking role for EEA1. In polarized cells (Madin-Darby canine kidney cells and hippocampal neurons), EEA1 is present on a subset of “basolateral-type” endosomal compartments, suggesting that EEA1 regulates specific endocytic pathways. In both epithelial cells and fibroblastic cells, EEA1 and a transfected apical endosomal marker, endotubin, label distinct endosomal populations. Hence, there are at least two distinct sets of early endosomes in polarized and nonpolarized mammalian cells. EEA1 could provide specificity and directionality to fusion events occurring in a subset of these endosomes in polarized and nonpolarized cells.

Entry, fate and degradation of DNA nanocages in mammalian cells: a matter of receptors

Nanoscale ◽  
2018 ◽  
Vol 10 (25) ◽  
pp. 12078-12086 ◽  
Author(s):  
Sofia Raniolo ◽  
Giulia Vindigni ◽  
Valeria Unida ◽  
Alessio Ottaviani ◽  
Elena Romano ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Endocytic Pathways

DNA nanocages, internalized by catabolic (LOX-1) or anabolic (αFR) receptors, traffic through diverse endocytic pathways and show different intracellular stability.

scholarly journals Existence of a novel clathrin-independent endocytic pathway in yeast that depends on Rho1 and formin

2011 ◽  
Vol 195 (4) ◽  
pp. 657-671 ◽  
Author(s):  
Derek C. Prosser ◽  
Theodore G. Drivas ◽  
Lymarie Maldonado-Báez ◽  
Beverly Wendland
Keyword(s):  
Mammalian Cells ◽  
Model Organism ◽  
Adaptor Proteins ◽  
Endocytic Pathway ◽  
Complex Protein ◽  
Endocytic Pathways ◽  
In Cells

Yeast is a powerful model organism for dissecting the temporal stages and choreography of the complex protein machinery during endocytosis. The only known mechanism for endocytosis in yeast is clathrin-mediated endocytosis, even though clathrin-independent endocytic pathways have been described in other eukaryotes. Here, we provide evidence for a clathrin-independent endocytic pathway in yeast. In cells lacking the clathrin-binding adaptor proteins Ent1, Ent2, Yap1801, and Yap1802, we identify a second endocytic pathway that depends on the GTPase Rho1, the downstream formin Bni1, and the Bni1 cofactors Bud6 and Spa2. This second pathway does not require components of the better-studied endocytic pathway, including clathrin and Arp2/3 complex activators. Thus, our results reveal the existence of a second pathway for endocytosis in yeast, which suggests similarities with the RhoA-dependent endocytic pathways of mammalian cells.

scholarly journals Clathrin-independent pathways do not contribute significantly to endocytic flux

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Vassilis Bitsikas ◽  
Ivan R Corrêa ◽  
Benjamin J Nichols
Keyword(s):  
Mammalian Cells ◽  
High Temporal Resolution ◽  
Coated Pits ◽  
Alternative Pathways ◽  
Specific Proteins ◽  
Clathrin Adaptor ◽  
And Function ◽  
Endocytic Vesicles ◽  
Data Call ◽  
Endocytic Pathways

Several different endocytic pathways have been proposed to function in mammalian cells. Clathrin-coated pits are well defined, but the identity, mechanism and function of alternative pathways have been controversial. Here we apply universal chemical labelling of plasma membrane proteins to define all primary endocytic vesicles, and labelling of specific proteins with a reducible SNAP-tag substrate. These approaches provide high temporal resolution and stringent discrimination between surface-connected and intracellular membranes. We find that at least 95% of the earliest detectable endocytic vesicles arise from clathrin-coated pits. GPI-anchored proteins, candidate cargoes for alternate pathways, are also found to enter the cell predominantly via coated pits. Experiments employing a mutated clathrin adaptor reveal distinct mechanisms for sorting into coated pits, and thereby explain differential effects on the uptake of transferrin and GPI-anchored proteins. These data call for a revision of models for the activity and diversity of endocytic pathways in mammalian cells.

scholarly journals Cell-penetrating peptides and antimicrobial peptides: how different are they?

2006 ◽  
Vol 399 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Sónia Troeira Henriques ◽  
Manuel Nuno Melo ◽  
Miguel A. R. B. Castanho
Keyword(s):  
Cell Membrane ◽  
Antimicrobial Peptides ◽  
Cellular Uptake ◽  
Mammalian Cells ◽  
Cell Penetrating Peptides ◽  
Host Cells ◽  
Cell Penetrating ◽  
New Perspective ◽  
Pathogenic Agents ◽  
Endocytic Pathways

Some cationic peptides, referred to as CPPs (cell-penetrating peptides), have the ability to translocate across biological membranes in a non-disruptive way and to overcome the impermeable nature of the cell membrane. They have been successfully used for drug delivery into mammalian cells; however, there is no consensus about the mechanism of cellular uptake. Both endocytic and non-endocytic pathways are supported by experimental evidence. The observation that some AMPs (antimicrobial peptides) can enter host cells without damaging their cytoplasmic membrane, as well as kill pathogenic agents, has also attracted attention. The capacity to translocate across the cell membrane has been reported for some of these AMPs. Like CPPs, AMPs are short and cationic sequences with a high affinity for membranes. Similarities between CPPs and AMPs prompted us to question if these two classes of peptides really belong to unrelated families. In this Review, a critical comparison of the mechanisms that underlie cellular uptake is undertaken. A reflection and a new perspective about CPPs and AMPs are presented.

scholarly journals Antigen B from Echinococcus granulosus enters mammalian cells by endocytic pathways

2018 ◽  
Vol 12 (5) ◽  
pp. e0006473 ◽  
Author(s):  
Edileuza Danieli da Silva ◽  
Martin Cancela ◽  
Karina Mariante Monteiro ◽  
Henrique Bunselmeyer Ferreira ◽  
Arnaldo Zaha
Keyword(s):  
Echinococcus Granulosus ◽  
Mammalian Cells ◽  
Antigen B ◽  
Endocytic Pathways

Ultrastructural Alterations in Hela Cells Induced by Spider Venom

1967 ◽  
Vol 25 ◽  
pp. 20-21
Author(s):  
Dale E. McClendon ◽  
Paul N. Morgan ◽  
Bernard L. Soloff
Keyword(s):  
Growth Medium ◽  
Mammalian Cells ◽  
Carcinoma Cells ◽  
Venom Protein ◽  
Sterile Saline ◽  
Carbon Coated ◽  
Available Information ◽  
Loxosceles Reclusa ◽  
Essential Growth ◽  
Solution Cultures

It has been observed that minute amounts of venom from the brown recluse spider, Loxosceles reclusa, are capable of producing cytotoxic changes in cultures of certain mammalian cells (Morgan and Felton, 1965). Since there is little available information concerning the effect of venoms on susceptible cells, we have attempted to characterize, at the electron microscope level, the cytotoxic changes produced by the venom of this spider.Cultures of human epithelial carcinoma cells, strain HeLa, were initiated on sterile, carbon coated coverslips contained in Leighton tubes. Each culture was seeded with approximately 1x105 cells contained in 1.5 ml of a modified Eagle's minimum essential growth medium prepared in Hank's balanced salt solution. Cultures were incubated at 36° C. for three days prior to the addition of venom. The venom was collected from female brown recluse spiders and diluted in sterile saline. Protein determinations on the venom-were made according to the spectrophotometric method of Waddell (1956). Approximately 10 μg venom protein per ml of fresh medium was added to each culture after discarding the old growth medium. Control cultures were treated similarly, except that no venom was added. All cultures were reincubated at 36° C.

Use of Uranium-Labeled Antibodies for Electron Microscopic Localization of Various Antigens in Mammalian Cells

1967 ◽  
Vol 25 ◽  
pp. 136-137
Author(s):  
J. P. Petrali ◽  
E. J. Donati ◽  
L. A. Sternberger
Keyword(s):  
Endoplasmic Reticulum ◽  
Hela Cells ◽  
Mammalian Cells ◽  
Specific Antiserum ◽  
Electron Microscopic ◽  
E Coli ◽  
Cytoplasmic Membranes ◽  
Viral Progeny ◽  
Ultrathin Sections ◽  
Electron Microscopic Localization

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

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