Apo-transferrin is internalized and routed differently from Fe-transferrin by caco-2 cells: a confocal microscopy study of vesicular transport in intestinal cells.
AuthorsAlvarez-Hernandez X, Smith M, Glass J
JournalBlood
PubMed ID10627487
'Caco-2 cells grown as monolayers on porous membranes in bicameral chambers have been used to study the transport of Fe from the apical (lumenal) chamber to the basal (serosal) chamber. The transport of Fe is stimulated by the presence of either apo-transferrin (apo-Tf) or ferri-transferrin (Fe-Tf) in the basal chamber ... More
Tamoxifen inhibits acidification in cells independent of the estrogen receptor.
AuthorsAltan N, Chen Y, Schindler M, Simon SM
JournalProc Natl Acad Sci U S A
PubMed ID10200279
Tamoxifen has been reported to have numerous physiological effects that are independent of the estrogen receptor, including sensitization of resistant tumor cells to many chemotherapeutic agents. Drug-resistant cells sequester weak base chemotherapeutics in acidic organelles away from their sites of action in the cytosol and nucleus. This work reports that ... More
A human dynamin-related protein controls the distribution of mitochondria.
AuthorsSmirnova E, Shurland DL, Ryazantsev SN, van der Bliek AM
JournalJ Cell Biol
PubMed ID9786947
Mitochondria exist as a dynamic tubular network with projections that move, break, and reseal in response to local environmental changes. We present evidence that a human dynamin-related protein (Drp1) is specifically required to establish this morphology. Drp1 is a GTPase with a domain structure similar to that of other dynamin ... More
A mechanism for tamoxifen-mediated inhibition of acidification.
AuthorsChen Y, Schindler M, Simon SM
JournalJ Biol Chem
PubMed ID10373441
Tamoxifen has been reported to inhibit acidification of cytoplasmic organelles in mammalian cells. Here, the mechanism of this inhibition is investigated using in vitro assays on isolated organelles and liposomes. Tamoxifen inhibited ATP-dependent acidification in organelles from a variety of sources, including isolated microsomes from mammalian cells, vacuoles from Saccharomyces ... More
Defective acidification in human breast tumor cells and implications for chemotherapy.
AuthorsAltan N, Chen Y, Schindler M, Simon SM
JournalJ Exp Med
PubMed ID9584137
Multidrug resistance (MDR) is a significant problem in the treatment of cancer. Chemotherapeutic drugs distribute through the cyto- and nucleoplasm of drug-sensitive cells but are excluded from the nucleus in drug-resistant cells, concentrating in cytoplasmic organelles. Weak base chemotherapeutic drugs (e.g., anthracyclines and vinca alkaloids) should concentrate in acidic organelles. ... More
Bacterial lipopolysaccharide can enter monocytes via two CD14-dependent pathways.
AuthorsKitchens RL, Wang P, Munford RS
JournalJ Immunol
PubMed ID9820530
Host recognition and disposal of LPS, an important Gram-negative bacterial signal molecule, may involve intracellular processes. We have therefore analyzed the initial pathways by which LPS, a natural ligand of glycosylphosphatidylinositol (GPI)-anchored CD14 (CD14-GPI), enters CD14-expressing THP-1 cells and normal human monocytes. Exposure of the cells to hypertonic medium obliterated ... More
Role of endocytosis in the internalization of spermidine-C(2)-BODIPY, a highly fluorescent probe of polyamine transport.
AuthorsSoulet D, Covassin L, Kaouass M, Charest-Gaudreault R, Audette M, Poulin R
JournalBiochem J
PubMed ID12097141
The mechanism of transmembrane polyamine internalization in mammalian cells remains unknown. A novel fluorescent spermidine conjugate [Spd-C(2)-BODIPY; N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionyl)-N'-(S -[spermidine-(N(4)-ethyl)]thioacetyl)ethylenediamine] was synthesized from N(4)-(mercaptoethyl)spermidine by a simple, one-step coupling procedure. In Chinese-hamster ovary (CHO) cells, Spd-C(2)-BODIPY accumulation was inhibited by exogenous putrescine, spermidine and spermine, was subject to feedback transport inhibition ... More
Evidence for nonvectorial, retrograde transferrin trafficking in the early endosomes of HEp2 cells.
AuthorsGhosh RN, Maxfield FR
JournalJ Cell Biol
PubMed ID7860630
We have previously characterized the trafficking of transferrin (Tf) through HEp2 human carcinoma cells (Ghosh, R. N., D. L. Gelman, and F. R. Maxfield, 1994. J. Cell Sci. 107:2177-2189). Early endosomes in these cells are comprised of both sorting endosomes and recycling compartments, which are distinct separate compartments. Endocytosed Tf ... More
Targeting of scavenger receptor class B type I by synthetic amphipathic alpha-helical-containing peptides blocks lipopolysaccharide (LPS) uptake and LPS-induced pro-inflammatory cytokine responses in THP-1 monocyte cells.
AuthorsBocharov AV, Baranova IN, Vishnyakova TG, Remaley AT, Csako G, Thomas F, Patterson AP, Eggerman TL
JournalJ Biol Chem
PubMed ID15199068
Human scavenger receptor class B type I, CLA-1, mediates lipopolysaccharide (LPS) binding and internalization (Vishnyakova, T. G., Bocharov, A. V., Baranova, I. N., Chen, Z., Remaley, A. T., Csako, G., Eggerman, T. L., and Patterson, A. P. (2003) J. Biol. Chem. 278, 22771-22780). Because one of the recognition motifs in ... More