Regulation of EGF Receptors and Nuclear Protooncogenes by Estrogen

AbstractThe endosomal system provides rich signal processing capabilities for responses elicited by growth factor receptors and their ligands. At the single cell level, endosomal trafficking becomes a critical component of signal processing, as exemplified by the epidermal growth factor (EGF) receptors. Activated EGFRs are trafficked to the phosphatase-enriched peri-nuclear region (PNR), where they are dephosphorylated and degraded. The details of the mechanisms that govern the movements of stimulated EGFRs towards the PNR, are not completely known. Here, exploiting the advantages of lattice light-sheet microscopy, we show that EGFR activation by EGF triggers a transient calcium increase causing a whole-cell level redistribution of Adaptor Protein, Phosphotyrosine Interacting with PH Domain And Leucine Zipper 1 (APPL1) from pre-existing endosomes within one minute, the rebinding of liberated APPL1 directly to EGFR, and the dynein-dependent translocation of APPL1-EGF-bearing endosomes to the PNR within ten minutes. The cell spanning, fast acting network that we reveal integrates a cascade of events dedicated to the cohort movement of activated EGF receptors. Our findings support the intriguing proposal that certain endosomal pathways have shed some of the stochastic strategies of traditional trafficking and have evolved processes that provide the temporal predictability that typify canonical signaling.

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Insulin-EGF receptor chimerae mediate tyrosine transphosphorylation and serine/threonine phosphorylation of kinase-deficient EGF receptors

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)92903-0 ◽

1991 ◽

Vol 266 (15) ◽

pp. 9900-9906

Author(s):

S. Tartare ◽

R. Ballotti ◽

R. Lammers ◽

F. Alengrin ◽

T. Dull ◽

...

Keyword(s):

Egf Receptor ◽

Egf Receptors

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E3-13.7 Integral Membrane Proteins Encoded by Human Adenoviruses Alter Epidermal Growth Factor Receptor Trafficking by Interacting Directly with Receptors in Early Endosomes

Molecular Biology of the Cell ◽

10.1091/mbc.11.10.3559 ◽

2000 ◽

Vol 11 (10) ◽

pp. 3559-3572 ◽

Cited By ~ 21

Author(s):

Denise Crooks ◽

Song Jae Kil ◽

J. Michael McCaffery ◽

Cathleen Carlin

Keyword(s):

Plasma Membrane ◽

Membrane Protein ◽

Viral Protein ◽

Egf Receptor ◽

Receptor Trafficking ◽

Model Systems ◽

Egf Receptors ◽

Down Regulation ◽

Human Adenoviruses ◽

Early Endosomes

Animal cell viruses provide valuable model systems for studying many normal cellular processes, including membrane protein sorting. The focus of this study is an integral membrane protein encoded by the E3 transcription region of human adenoviruses called E3-13.7, which diverts recycling EGF receptors to lysosomes without increasing the rate of receptor internalization or intrinsic receptor tyrosine kinase activity. Although E3-13.7 can be found on the plasma membrane when it is overexpressed, its effect on EGF receptor trafficking suggests that the plasma membrane is not its primary site of action. Using cell fractionation and immunocytochemical experimental approaches, we now report that the viral protein is located predominantly in early endosomes and limiting membranes of endosome-to-lysosome transport intermediates called multivesicular endosomes. We also demonstrate that E3-13.7 physically associates with EGF receptors undergoing E3-13.7–mediated down-regulation in early endosomes. Receptor–viral protein complexes then dissociate, and EGF receptors proceed to lysosomes, where they are degraded, while E3-13.7 is retained in endosomes. We conclude that E3-13.7 is a resident early endocytic protein independent of EGF receptor expression, because it has identical intracellular localization in mouse cells lacking endogenous receptors and cells expressing a human cytomegalovirus-driven receptor cDNA. Finally, we demonstrate that EGF receptor residues 675–697 are required for E3-13.7–mediated down-regulation. Interestingly, this sequence includes a known EGF receptor leucine-based lysosomal sorting signal used during ligand-induced trafficking, which is also conserved in the viral protein. E3-13.7, therefore, provides a novel model system for determining the molecular basis of selective membrane protein transport in the endocytic pathway. Our studies also suggest new paradigms for understanding EGF receptor sorting in endosomes and adenovirus pathogenesis.

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Singlemolecule visualization of the interaction between EGF receptors and their adaptor proteins

Seibutsu Butsuri ◽

10.2142/biophys.41.s118_4 ◽

2001 ◽

Vol 41 (supplement) ◽

pp. S118

Author(s):

K. Ota ◽

M. Morimatsu ◽

Y. Sako ◽

M. Murata ◽

T. Yanagida

Keyword(s):

Adaptor Proteins ◽

Egf Receptors

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Expression of transforming growth factor alpha during development

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y88-183 ◽

1988 ◽

Vol 66 (8) ◽

pp. 1113-1121 ◽

Cited By ~ 10

Author(s):

V. K. M. Han ◽

A. J. D'Ercole ◽

D. C. Lee

Keyword(s):

In Situ Hybridization ◽

Growth Factor ◽

Mrna Expression ◽

Transforming Growth Factor ◽

Transforming Growth Factor Alpha ◽

Egf Receptors ◽

Hybridization Histochemistry ◽

In Situ Hybridization Histochemistry ◽

Factor Alpha

Transforming growth factors (TGFs) are polypeptides that are produced by transformed and tumour cells, and that can confer phenotypic properties associated with transformation on normal cells in culture. One of these growth-regulating molecules, transforming growth factor alpha (TGF-α), is a 50 amino acid polypeptide that is related to epidermal growth factor (EGF) and binds to the EGF receptor. Previous studies have shown that TGF-α is expressed during rodent embryogenesis between 7 and 14 days gestation. To investigate the cellular sites of TGF-α mRNA expression during development, we have performed Northern analyses and in situ hybridization histochemistry on the conceptus and maternal tissues at various gestational ages. Contrary to previous reports, both Northern analyses and in situ hybridization histochemistry indicate that TGF-α mRNA is predominantly expressed in the maternal decidua and not in the embryo. Decidual expression is induced following implantation, peaks at day 8, and declines through day 15 when the decidua is being resorbed. In situ hybridization revealed that expression of TGF-α mRNA is highest in the region of decidua adjacent to the embryo and is low or nondetectable in the uterus, placenta, and embryo. In addition, we could not detect TGF-α mRNA expression in other maternal tissues, indicating that the induction of TGF-α transcripts in the decidua is tissue specific, and not a pleiotropic response to changes in hormonal milieu that occur during pregnancy. The developmentally regulated expression of TGF-α mRNA in the decidua, together with the presence of EGF receptors in this tissue, suggests that this peptide may stimulate mitosis and angiogenesis locally by an autocrine mechanism. Because EGF receptors are also present in the embryo and placenta, TGF-α may act on these tissues by a paracrine or endocrine mechanism.

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Insulin-receptor phosphotyrosyl-protein phosphatases

Biochemical Journal ◽

10.1042/bj2560893 ◽

1988 ◽

Vol 256 (3) ◽

pp. 893-902 ◽

Cited By ~ 26

Author(s):

M J King ◽

G J Sale

Keyword(s):

Insulin Receptor ◽

Phosphatase Activity ◽

Rat Liver ◽

Protein Phosphatase ◽

Egf Receptor ◽

Soluble Fraction ◽

Protein Phosphatases ◽

Egf Receptors ◽

Cell Extracts ◽

Dependent Protein

Calmodulin-dependent protein phosphatase has been proposed to be an important phosphotyrosyl-protein phosphatase. The ability of the enzyme to attack autophosphorylated insulin receptor was examined and compared with the known ability of the enzyme to act on autophosphorylated epidermal-growth-factor (EGF) receptor. Purified calmodulin-dependent protein phosphatase was shown to catalyse the complete dephosphorylation of phosphotyrosyl-(insulin receptor). When compared at similar concentrations, 32P-labelled EGF receptor was dephosphorylated at greater than 3 times the rate of 32P-labelled insulin receptor; both dephosphorylations exhibited similar dependence on metal ions and calmodulin. Native phosphotyrosyl-protein phosphatases in cell extracts were also characterized. With rat liver, heart or brain, most (75%) of the native phosphatase activity against both 32P-labelled insulin and EGF receptors was recovered in the particulate fraction of the cell, with only 25% in the soluble fraction. This subcellular distribution contrasts with results of previous studies using artificial substrates, which found most of the phosphotyrosyl-protein phosphatase activity in the soluble fraction of the cell. Properties of particulate and soluble phosphatase activity against 32P-labelled insulin and EGF receptors are reported. The contribution of calmodulin-dependent protein phosphatase activity to phosphotyrosyl-protein phosphatase activity in cell fractions was determined by utilizing the unique metal-ion dependence of calmodulin-dependent protein phosphatase. Whereas Ni2+ (1 mM) markedly activated the calmodulin-dependent protein phosphatase, it was found to inhibit potently both particulate and soluble phosphotyrosyl-protein phosphatase activity. In fractions from rat liver, brain and heart, total phosphotyrosyl-protein phosphatase activity against both 32P-labelled receptors was inhibited by 99.5 +/- 6% (mean +/- S.E.M., 30 observations) by Ni2+. Results of Ni2+ inhibition studies were confirmed by other methods. It is concluded that in cell extracts phosphotyrosyl-protein phosphatases other than calmodulin-dependent protein phosphatase are the major phosphotyrosyl-(insulin receptor) and -(EGF receptor) phosphatases.

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