scholarly journals Inhibition of Transferrin Recycling and Endosome Tubulation by Phospholipase A2Antagonists

2001 ◽  
Vol 276 (50) ◽  
pp. 47361-47370 ◽  
Author(s):  
Paul de Figueiredo ◽  
Anne Doody ◽  
Renée S. Polizotto ◽  
Daniel Drecktrah ◽  
Salli Wood ◽  
...  
Keyword(s):  
Cell Surface ◽  
Molecular Mechanism ◽  
Golgi Complex ◽  
Broad Spectrum ◽  
Tubule Formation ◽  
Recycling Endosomes ◽  
Low Concentrations ◽  
A Cell ◽  
Recycling Pathway ◽  
Lines Of Evidence

We report here that a broad spectrum of phospholipase A2(PLA2) antagonists produce a concentration-dependent, differential block in the endocytic recycling pathway of transferrin (Tf) and Tf receptors (TfRs) but have no acute affect on Tf uptake from the cell surface. At low concentrations of antagonists (∼1 μm), Tf and TfR accumulated in centrally located recycling endosomes, whereas at higher concentrations (∼10 μm), Tf-TfR accumulated in peripheral sorting endosomes. Several independent lines of evidence suggest that this inhibition of recycling may result from the inhibition of tubule formation. First, BFA-stimulated endosome tubule formation was similarly inhibited by PLA2antagonists. Second, endocytosed tracers were found in larger spherical endosomes in the presence of PLA2antagonists. And third, endosome tubule formation in a cell-free, cytosol-dependent reconstitution system was equally sensitive PLA2antagonists. These results are consistent with the conclusion that endosome membrane tubules are formed by the action of a cytoplasmic PLA2and that PLA2-dependent tubules are involved in intracellular recycling of Tf and TfR. When taken together with previous studies on the Golgi complex, these results also indicate that an intracellular PLA2activity provides a novel molecular mechanism for inducing tubule formation from multiple organelles.

scholarly journals Intracellular movement of cell surface receptors after endocytosis: resialylation of asialo-transferrin receptor in human erythroleukemia cells.

1985 ◽  
Vol 100 (3) ◽  
pp. 826-834 ◽  
Author(s):  
M D Snider ◽  
O C Rogers
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Golgi Complex ◽  
Transferrin Receptor ◽  
Cell Surface Receptor ◽  
Surface Receptors ◽  
Erythroleukemia Cells ◽  
Intracellular Movement ◽  
Surface Receptor ◽  
A Cell

The intracellular movement of cell surface transferrin receptor (TfR) after internalization was studied in K562 cultured human erythroleukemia cells. The sialic acid residues of the TfR glycoprotein were used to monitor transport to the Golgi complex, the site of sialyltransferases. Surface-labeled cells were treated with neuraminidase, and readdition of sialic acid residues, monitored by isoelectric focusing of immunoprecipitated TfR, was used to assess the movement of receptor to sialyltransferase-containing compartments. Asialo-TfR was resialylated by the cells with a half-time of 2-3 h. Resialylation occurred in an intracellular organelle, since it was inhibited by treatments that allow internalization of surface components but block transfer out of the endosomal compartment. Moreover, roughly half of the resialylated molecules were cleaved when cells were retreated with neuraminidase after culturing, indicating that this fraction of the molecules had returned to the cell surface. These results suggest that TfR is transported from the cell surface to the Golgi complex, the intracellular site of sialyltransferases, and then returns to the cell surface. This pathway, which has not been previously described for a cell surface receptor, may be different from the route followed by TfR in iron uptake, since reported rates of transferrin uptake and release are significantly more rapid than the resialylation of asialo-TfR.

The PDZ-interaction of the intestinal anion exchanger downregulated in adenoma (DRA; SLC26A3) facilitates its movement into Rab11a-positive recycling endosomes

2013 ◽  
Vol 304 (11) ◽  
pp. G980-G990 ◽  
Author(s):  
S. Lissner ◽  
C.-J. Hsieh ◽  
L. Nold ◽  
K. Bannert ◽  
P. Bodammer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Surface Expression ◽  
Dominant Negative ◽  
Cell Surface Expression ◽  
Dominant Negative Mutant ◽  
Recycling Endosomes ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Recycling Pathway

Electroneutral NaCl absorption in the ileum and colon is mediated by downregulated in adenoma (DRA) (Cl-/HCO3- exchanger; SLC26A3) and Na+/H+ exchanger 3 (NHE3, SLC9A3). Surface expression of transport proteins undergoes basal and regulated recycling by endo- and exocytosis. Expression and activity of DRA in the plasma membrane depend on intact lipid rafts, phosphatidylinositol 3-kinase (PI3-kinase), and the PDZ interaction of DRA. However, it is unknown how the PDZ interaction of DRA affects its trafficking to the cell surface. Therefore, the (re)cycling pathway of DRA was investigated in HEK cells stably expressing enhanced green fluorescent protein (EGFP)-DRA or EGFP-DRA-ETKFminus (a mutant lacking the PDZ interaction motif). Early, late, and recycling endosomes were immunoisolated by precipitating stably transfected mCherry-hemagglutinin (HA)-Rab5a, -7a, or -11a. EGFP-DRA and EGFP-DRA-ETKFminus were equally present in early endosomes. In recycling endosomes, wild-type DRA was preferentially present, whereas, in late endosomes, DRA-ETKF-minus dominated. Correspondingly, EGFP-DRA colocalized with mCherry-HA-Rab11a in recycling endosomes, whereas EGFP-DRA-ETKFminus colocalized with mCherry-HA-Rab7a in late endosomes. Functionally, this different distribution was reflected by a shorter half-life of the mutant DRA. Transient expression of dominant-negative Rab11aS25N inhibited the activity (-17%, P < 0.05) and the cell surface expression of DRA (-30%, P < 0.05). Transient transfection of Rab4a or its dominant-negative mutant Rab4aS22N was without effect and thus excluded participation of the rapid recycling pathway. Taken together, the PDZ interaction of DRA facilitates its movement into Rab11a-positive recycling endosomes, from where it is inserted in the plasma membrane. A scenario emerges where specific PDZ adaptor proteins are present along several compartments of the endocytosis-recycling pathway.

scholarly journals Insulin Increases Cell Surface GLUT4 Levels by Dose Dependently Discharging GLUT4 into a Cell Surface Recycling Pathway

2004 ◽  
Vol 24 (14) ◽  
pp. 6456-6466 ◽  
Author(s):  
Roland Govers ◽  
Adelle C. F. Coster ◽  
David E. James
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Glucose Transporter ◽  
Insulin Dose ◽  
Cell Types ◽  
Insulin Stimulation ◽  
Intracellular Compartments ◽  
A Cell ◽  
Recycling Pathway ◽  
Glucose Transporter Glut4

ABSTRACT The insulin-responsive glucose transporter GLUT4 plays an essential role in glucose homeostasis. A novel assay was used to study GLUT4 trafficking in 3T3-L1 fibroblasts/preadipocytes and adipocytes. Whereas insulin stimulated GLUT4 translocation to the plasma membrane in both cell types, in nonstimulated fibroblasts GLUT4 readily cycled between endosomes and the plasma membrane, while this was not the case in adipocytes. This efficient retention in basal adipocytes was mediated in part by a C-terminal targeting motif in GLUT4. Insulin caused a sevenfold increase in the amount of GLUT4 molecules present in a trafficking cycle that included the plasma membrane. Strikingly, the magnitude of this increase correlated with the insulin dose, indicating that the insulin-induced appearance of GLUT4 at the plasma membrane cannot be explained solely by a kinetic change in the recycling of a fixed intracellular GLUT4 pool. These data are consistent with a model in which GLUT4 is present in a storage compartment, from where it is released in a graded or quantal manner upon insulin stimulation and in which released GLUT4 continuously cycles between intracellular compartments and the cell surface independently of the nonreleased pool.

scholarly journals Phosphorylation of a cell surface 112 kDa protein by an ecto-protein kinase in rat L6 myoblasts

1991 ◽  
Vol 279 (2) ◽  
pp. 467-474 ◽  
Author(s):  
X Y Chen ◽  
T C Y Lo
Keyword(s):  
Protein Kinase ◽  
Cell Surface ◽  
Myogenic Differentiation ◽  
Protein Profile ◽  
Extracellular Atp ◽  
Experimental Conditions ◽  
Intact Cells ◽  
Low Concentrations ◽  
Km Value ◽  
A Cell

Studies with subconfluent day 2 cultures of rat myoblasts revealed that a cell surface 112 kDa protein could be phosphorylated by extracellular ATP. Analysis of the phosphorylated 112 kDa protein suggested the involvement of a serine protein kinase. The following evidence indicated the cell surface location of this protein kinase: (i) extracellular ATP was unable to penetrate the cell membrane under our experimental conditions; (ii) the phosphorylated protein profile of intact cells differed significantly from that of broken cells; (iii) the phosphorylation of the 112 kDa protein could be abolished by pretreatment of cells with very low concentrations of trypsin; (iv) the phosphorylated 112 kDa protein could be dephosphorylated by exogenously added alkaline phosphatase; (v) the phosphorylation of the 112 kDa protein was inhibited by exogenously added proteins; and (vi) exogenously added proteins could be phosphorylated by intact cells under similar experimental conditions. The phosphorylated 112 kDa protein was detected only when the reaction was carried out in the presence of Ca2+, Mg2+, and F- ions. Kinetic analysis that revealed that the Km value of the ecto-protein kinase for ATP was 0.04 microM, and the Vmax. value for phosphorylation of the 112 kDa protein was 1.67 x 10(-4) pmol/min per 10(5) cells. Data presented in the accompanying paper [Chen & Lo (1991) Biochem. J. 279, 475-482] show that there was a constant and adequate supply of ATP on the cell surface of rat myoblasts for efficient functioning of this protein kinase, and that mutants defective in either the ecto-protein kinase or the 112 kDa protein were also impaired in myogenic differentiation. This and other biochemical studies suggest that the ecto-protein kinase and the 112 kDa protein might play important roles in myogenic differentiation.

Broad-Spectrum Antiviral Property of Polyoxometalate Localized on a Cell Surface

2014 ◽  
Vol 6 (12) ◽  
pp. 9785-9789 ◽  
Author(s):  
Juan Wang ◽  
Yang Liu ◽  
Kun Xu ◽  
Yanfei Qi ◽  
Jun Zhong ◽  
...  
Keyword(s):  
Cell Surface ◽  
Broad Spectrum ◽  
Antiviral Property ◽  
A Cell

scholarly journals The B cell antigen CD75 is a cell surface sialytransferase.

1990 ◽  
Vol 172 (2) ◽  
pp. 641-643 ◽  
Author(s):  
I Stamenkovic ◽  
H C Asheim ◽  
A Deggerdal ◽  
H K Blomhoff ◽  
E B Smeland ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Cell Surface ◽  
B Cell ◽  
Golgi Complex ◽  
Cdna Clone ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Cell Antigen ◽  
A Cell

In this work we have isolated a cDNA clone encoding the B cell antigen CD75. The amino acid sequence of CD75 is shown to be identical to that of human alpha 2,6 sialyltransferase, believed to be primarily associated with the Golgi complex. This is the first demonstration of cell surface expression of sialytransferase which, in B cells, may play an important role in intercellular adhesion and antigen presentation events.

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