scholarly journals The effect of epidermal growth factor (EGF) on the differentiation of the rough endoplasmic reticulum in fetal mouse small intestine in organ culture.

1981 ◽  
Vol 29 (6) ◽  
pp. 765-770 ◽  
Author(s):  
J F Beaulieu ◽  
R Calvert
Keyword(s):  
Endoplasmic Reticulum ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Organ Culture ◽  
Rough Endoplasmic Reticulum ◽  
Fetal Mouse ◽  
Absorptive Cells ◽  
Mouse Small Intestine ◽  
Epidermal Growth ◽  
Mouse Fetuses

The differentiation of the rough endoplasmic reticulum (RER) of mouse duodenal absorptive cells located at the tip of the villi at 17 days of gestation was compared to that of absorptive cells in duodenal explants of 15-day-old mouse fetuses cultured for 72 hr 1) with Trowell T8 medium (without insulin) alone or supplemented 2) with epidermal growth factor (EGF; 100 ng/ml) or 3) with 25% bovine amniotic fluid (BAF). Glucose-6-phosphatase activity (G6Pase) was localized cytochemically to ensure a better identification of the RER. The intersections of a double lattice falling over and outside the RER were counted and the percentage of intersections over the RER was estimated. With this method, the extent of the RER is not statistically different when the absorptive cells in utero are compared to those of explants cultured with EGF. However, the extent of the RER in the absorptive cells cultured with Trowell T8 medium alone or supplemented with BAF is 50% lower than in the former two groups. It is concluded that EGF promotes the maturation of duodenal absorptive cells in organ culture.

scholarly journals Sch proteins are localized on endoplasmic reticulum membranes and are redistributed after tyrosine kinase receptor activation.

1996 ◽  
Vol 16 (5) ◽  
pp. 1946-1954 ◽  
Author(s):  
L V Lotti ◽  
L Lanfrancone ◽  
E Migliaccio ◽  
C Zompetta ◽  
G Pelicci ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Rough Endoplasmic Reticulum ◽  
Receptor Tyrosine Kinase ◽  
Receptor Activation ◽  
Kinase Activation ◽  
Epidermal Growth

The intracellular localization of Shc proteins was analyzed by immunofluorescence and immunoelectron microscopy in normal cells and cells expressing the epidermal growth factor receptor or the EGFR/erbB2 chimera. In unstimulated cells, the immunolabeling was localized in the central perinuclear area of the cell and mostly associated with the cytosolic side of rough endoplasmic reticulum membranes. Upon epidermal growth factor treatment and receptor tyrosine kinase activation, the immunolabeling became peripheral and was found to be associated with the cytosolic surface of the plasma membrane and endocytic structures, such as coated pits and endosomes, and with the peripheral cytosol. Receptor activation in cells expressing phosphorylation-defective mutants of Shc and erbB-2 kinase showed that receptor autophosphorylation, but not Shc phosphorylation, is required for redistribution of Shc proteins. The rough endoplasmic reticulum localization of Shc proteins in unstimulated cells and their massive recruitment to the plasma membrane, endocytic structures, and peripheral cytosol following receptor tyrosine kinase activation could account for multiple putative functions of the adaptor protein.

The presence of epidermal growth factor binding sites in the intracellular organelles of term human placenta

1986 ◽  
Vol 84 (1) ◽  
pp. 19-40
Author(s):  
N. Ramani ◽  
N. Chegini ◽  
C.V. Rao ◽  
P.G. Woost ◽  
G.S. Schultz
Keyword(s):  
Endoplasmic Reticulum ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Rough Endoplasmic Reticulum ◽  
Human Placenta ◽  
Binding Sites ◽  
Plasma Membranes ◽  
Smooth Endoplasmic Reticulum ◽  
Intracellular Organelles ◽  
Epidermal Growth

Highly purified lysosomes, rough and smooth endoplasmic reticulum, and Golgi apparatus, as well as microvillus plasma membranes, bound 125I-labelled epidermal growth factor ([125I]EGF) with similar affinity. Scatchard plots for all the organelles were curvilinear. The apparent number of available binding sites per mg protein of intracellular organelles was 27–71% of that found in microvillus plasma membranes. The bound and free [125I]EGF were not degraded by any of the organelles. Binding and dissociation of [125I]EGF in all organelles were dependent on the time and temperature of incubation. The specificity of [125I]EGF binding was similar in all organelles. The optimal pH for binding to lysosomes was 6.0, in contrast to 7.0 for all the other organelles. Exposure of different organelles to enzymes and protein-modifying reagents resulted in numerous binding differences between the intracellular organelles and microvillus plasma membranes. Covalent affinity labelling with [125I]EGF revealed two major proteins of 155 and 140(X10(3)) Mr in all the organelles. The 155 X 10(3) Mr protein was labelled predominantly in all organelles except rough endoplasmic reticulum, where both proteins were equally labelled. Addition of proteolytic inhibitors during isolation of organelles did not alter the pattern of [125I]EGF-labelled binding proteins found in the organelles. EGF also stimulated phosphorylation of the 155 and 140(X10(3)) Mr proteins in all the organelles. The 155 X 10(3) Mr protein was phosphorylated more than the 140 X 10(3) Mr protein in microvillus plasma membranes and smooth endoplasmic reticulum, whereas the 140 X 10(3) Mr protein was phosphorylated more than the 155 X 10(3) Mr protein in lysosomes and both proteins were equally phosphorylated in rough endoplasmic reticulum. Several organelles also contained minor [125I]EGF-binding proteins that did not show phosphorylation response and proteins that showed phosphorylation response but did not bind [125I]EGF. Thus, the present study demonstrates by a number of different criteria, that several intracellular organelles of term human placenta also contain EGF-binding and kinase activities.

Orientation of the v-erb-B gene product in the plasma membrane

1986 ◽  
Vol 6 (4) ◽  
pp. 1329-1333
Author(s):  
R C Schatzman ◽  
G I Evan ◽  
M L Privalsky ◽  
J M Bishop
Keyword(s):  
Endoplasmic Reticulum ◽  
Epidermal Growth Factor Receptor ◽  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Kinase Domain ◽  
Amino Terminus ◽  
Protein Kinase Domain ◽  
Epidermal Growth

The retroviral oncogene v-erb-B encodes a truncated version of the receptor for epidermal growth factor. To define the disposition of the v-erb-B protein within cells and across the plasma membrane, we raised antibodies against defined epitopes in the protein and used these in immunofluorescence to analyze cells transformed by v-erb-B. A small fraction of the v-erb-B protein was found on the plasma membrane in a clustered configuration. The bulk of the protein was located in the endoplasmic reticulum and Golgi apparatus. Epitopes near the amino terminus of the v-erb-B protein were displayed on the surface of the cell, whereas epitopes in the protein kinase domain were located exclusively within cells. We conclude that the v-erb-B protein spans the plasma membrane in a manner similar or identical to that of the epidermal growth factor receptor, even though the viral transforming protein does not possess the signal peptide that is thought to direct insertion of the receptor into the membrane.

Mechanism regulating nuclear calcium signalingThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

2006 ◽  
Vol 84 (3-4) ◽  
pp. 403-422 ◽  
Author(s):  
Anant N. Malviya ◽  
Christian Klein
Keyword(s):  
Endoplasmic Reticulum ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Calcium Signaling ◽  
Nuclear Membrane ◽  
Protein Fragment ◽  
Outer Nuclear Membrane ◽  
Nuclear Calcium ◽  
A Cell ◽  
Epidermal Growth

Although the outer nuclear membrane is continuous with the endoplasmic reticulum, it is possible to isolate nuclei both intact and free from endoplasmic reticulum contaminants. The outer and the inner nuclear membranes can be purified free from cross-contamination. Evidence in support of autonomous regulation of nuclear calcium signaling relies upon the investigations with isolated nuclei. Mechanisms for generating calcium signaling in the nucleus have been identified. Two calcium transporting systems, an ATP-dependant nuclear Ca2+-ATPase and an IP4-mediated inositol 1,3,4,5-tetrakisphosphate receptor, are located on the outer nuclear membrane. Thus, ATP and IP4, depending on external free calcium concentrations, are responsible for filling the nuclear envelope calcium pool. The inositol 1,4,5-trisphosphate receptor is located on the inner nuclear membrane with its ligand binding domain facing toward the nucleoplasm. Likewise, the ryanodine receptor is located on the inner nuclear membrane and its ligand cADP-ribose is generated within the nucleus. A 120 kDa protein fragment of nuclear PLC-γ1 is stimulated in vivo by epidermal growth factor nuclear signaling coincident with the time course of nuclear membrane epidermal growth factor receptor activation. Stimulated 120 kDa protein fragment interacts with PIKE, a nuclear GTPase, and together they form a complex with PI[3]kinase serving as a module for nuclear PI[3]K stimulation. Thus, the nucleus has its own IP3 generating system.

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