scholarly journals Heterogeneity of signal transduction at the subcellular level: microsphere-based focal EGF receptor activation and stimulation of Shc translocation

2001 ◽  
Vol 114 (13) ◽  
pp. 2437-2447
Author(s):  
Roland Brock ◽  
Thomas M. Jovin

Epidermal growth factor receptor (EGFR, erbB1) activation and translocation of the Shc adaptor protein to activated receptors were analyzed at the subcellular level by dual-label immunofluorescence and confocal laser scanning microscopy in conjunction with a new microsphere-based protocol. In the Quantitative Microsphere Recruitment Assay (QMRA) introduced here, epidermal growth factor-coated 1 μm diameter microspheres were distributed over the surface of adherent tissue culture cells expressing the receptor. High-resolution confocal microscopy of a fusion construct of the receptor and the green fluorescent protein expressed in Chinese hamster ovary cells demonstrated that engulfment and internalization of the microspheres occurred rapidly within minutes, and in a receptor activation-dependent manner. In human epidermoid carcinoma A431 cells, receptor activation and Shc translocation persisted over the 20-minute time course of the experiments. However, at the subcellular level the positive correlation of receptor activation and Shc translocation observed at 5-8 minutes dissipated, indicating a time-dependent decoupling of the two events and variation in the kinetics of signal transduction for different subcellular locations.

2000 ◽  
Vol 11 (5) ◽  
pp. 1801-1814 ◽  
Author(s):  
Anastasiya D. Blagoveshchenskaya ◽  
Daniel F. Cutler

In PC12 neuroendocrine cells, synaptic-like microvesicles (SLMV) are thought to be formed by two pathways. One pathway sorts the proteins to SLMV directly from the plasma membrane (or a specialized domain thereof) in an adaptor protein complex 2-dependent, brefeldin A (BFA)-insensitive manner. Another pathway operates via an endosomal intermediate, involves adaptor protein complex 3, and is BFA sensitive. We have previously shown that when expressed in PC12 cells, HRP-P-selectin chimeras are directed to SLMV mostly via the endosomal, BFA-sensitive route. We have now found that two endosomal intermediates are involved in targeting of HRP-P-selectin chimeras to SLMV. The first intermediate is the early, transferrin-positive, epidermal growth factor-positive endosome, from which exit to SLMV is controlled by the targeting determinants YGVF and KCPL, located within the cytoplasmic domain of P-selectin. The second intermediate is the late, transferrin-negative, epidermal growth factor-positive late endosome, from where HRP-P-selectin chimeras are sorted to SLMV in a YGVF- and DPSP-dependent manner. Both sorting steps, early endosomes to SLMV and late endosomes to SLMV, are affected by BFA. In addition, analysis of double mutants with alanine substitutions of KCPL and YGVF or KCPL and DPSP indicated that chimeras pass sequentially through these intermediates en route both to lysosomes and to SLMV. We conclude that a third site of formation for SLMV, the late endosomes, exists in PC12 cells.


2010 ◽  
Vol 30 (15) ◽  
pp. 3795-3804 ◽  
Author(s):  
Nicholas Ariotti ◽  
Hong Liang ◽  
Yufei Xu ◽  
Yueqiang Zhang ◽  
Yoshiya Yonekubo ◽  
...  

ABSTRACT Signal transduction is regulated by the lateral segregation of proteins into nanodomains on the plasma membrane. However, the molecular mechanisms that regulate the lateral segregation of cell surface receptors, such as receptor tyrosine kinases, upon ligand binding are unresolved. Here we used high-resolution spatial mapping to investigate the plasma membrane nanoscale organization of the epidermal growth factor (EGF) receptor (EGFR). Our data demonstrate that in serum-starved cells, the EGFR exists in preformed, cholesterol-dependent, actin-independent nanoclusters. Following stimulation with EGF, the number and size of EGFR nanoclusters increase in a time-dependent manner. Our data show that the formation of EGFR nanoclusters requires receptor tyrosine kinase activity. Critically, we show for the first time that production of phosphatidic acid by phospholipase D2 (PLD2) is essential for ligand-induced EGFR nanocluster formation. In accordance with its crucial role in regulating EGFR nanocluster formation, we demonstrate that modulating PLD2 activity tunes the degree of EGFR nanocluster formation and mitogen-activated protein kinase signal output. Together, these data show that EGFR activation drives the formation of signaling domains by regulating the production of critical second-messenger lipids and modifying the local membrane lipid environment.


1999 ◽  
Vol 10 (2) ◽  
pp. 417-434 ◽  
Author(s):  
Maria Rosaria Torrisi ◽  
Lavinia Vittoria Lotti ◽  
Francesca Belleudi ◽  
Roberto Gradini ◽  
Anna Elisabetta Salcini ◽  
...  

Eps15 is a substrate for the tyrosine kinase of the epidermal growth factor receptor (EGFR) and is characterized by the presence of a novel protein:protein interaction domain, the EH domain. Eps15 also stably binds the clathrin adaptor protein complex AP-2. Previous work demonstrated an essential role for eps15 in receptor-mediated endocytosis. In this study we show that, upon activation of the EGFR kinase, eps15 undergoes dramatic relocalization consisting of 1) initial relocalization to the plasma membrane and 2) subsequent colocalization with the EGFR in various intracellular compartments of the endocytic pathway, with the notable exclusion of coated vesicles. Relocalization of eps15 is independent of its binding to the EGFR or of binding of the receptor to AP-2. Furthermore, eps15 appears to undergo tyrosine phosphorylation both at the plasma membrane and in a nocodazole-sensitive compartment, suggesting sustained phosphorylation in endocytic compartments. Our results are consistent with a model in which eps15 undergoes cycles of association:dissociation with membranes and suggest multiple roles for this protein in the endocytic pathway.


2019 ◽  
Vol 20 (20) ◽  
pp. 5172 ◽  
Author(s):  
Qiongyao Hu ◽  
Shaohua Xu ◽  
Cheng Ye ◽  
Jingyi Jia ◽  
Lingling Zhou ◽  
...  

Epidermal growth factor (EGF) is a member of the EGF-like ligands family, which plays a vital role in cell proliferation, differentiation, and folliculogenesis through binding with EGF receptors, including ErbB1 (EGFR/HER1), ErbB2 (HER2), ErbB3 (HER3), and ErbB4 (HER4). In mammals, many functional roles of EGF have been reported in the ovaries and breasts. However, little is known about the functions of EGF in the pituitary, especially in teleost. In this study, using grass carp pituitary cells as the model, we try to examine the direct pituitary actions of EGF in teleost. Firstly, transcriptomic analysis showed that 599 different expressed genes (DEGs) between the control and EGF-treatment group were mainly involved in cell proliferation, cell migration, signal transduction, and transcriptional regulation. Then, we further confirmed that EGF could significantly induce UTS1, EGR1, and MMP13 mRNA expression in a time-and dose-dependent manner. The stimulatory actions of EGF on UTS1 and EGR1 mRNA expression were mediated by the MEK1/2/ERK1/2 and PI3K/AKT/mTOR pathways coupled with both ErbB1 and ErbB2 in grass carp pituitary cells. The receptor specificity and signal transductions for the corresponding responses on MMP13 mRNA expression were also similar, except that the ErbB2 and PI3K/AKT/mTOR pathway were not involved. As we know, MMP13 could release EGF from HB-EGF. Interestingly, our data also showed that the MMPs inhibitor BB94 could suppress EGF-induced UTS1 and EGR1 mRNA expression. These results, taken together, suggest that the stimulatory actions of EGF on UTS1 and EGR1 mRNA expression could be enhanced by EGF-induced MMP13 expression in the pituitary.


2006 ◽  
Vol 26 (2) ◽  
pp. 389-401 ◽  
Author(s):  
Lene E. Johannessen ◽  
Nina Marie Pedersen ◽  
Ketil Winther Pedersen ◽  
Inger Helene Madshus ◽  
Espen Stang

ABSTRACT In HeLa cells depleted of adaptor protein 2 complex (AP2) by small interfering RNA (siRNA) to the μ2 or α subunit or by transient overexpression of an AP2 sequestering mutant of Eps15, endocytosis of the transferrin receptor (TfR) was strongly inhibited. However, epidermal growth factor (EGF)-induced endocytosis of the EGF receptor (EGFR) was inhibited only in cells where the α subunit had been knocked down. By immunoelectron microscopy, we found that in AP2-depleted cells, the number of clathrin-coated pits was strongly reduced. When such cells were incubated with EGF, new coated pits were formed. These contained EGF, EGFR, clathrin, and Grb2 but not the TfR. The induced coated pits contained the α subunit, but labeling density was reduced compared to control cells. Induction of clathrin-coated pits required EGFR kinase activity. Overexpression of Grb2 with inactivating point mutations in N- or C-terminal SH3 domains or in both SH3 domains inhibited EGF-induced formation of coated pits efficiently, even though Grb2 SH3 mutations did not block activation of mitogen-activated protein kinase (MAPK) or phosphatidylinositol 3-kinase (PI3K). Our data demonstrate that EGFR-induced signaling and Grb2 are essential for formation of clathrin-coated pits accommodating the EGFR, while activation of MAPK and PI3K is not required.


2002 ◽  
Vol 283 (3) ◽  
pp. L531-L540 ◽  
Author(s):  
Kazuhiro Kohri ◽  
Iris F. Ueki ◽  
Jay A. Nadel

Neutrophil products are implicated in hypersecretory airway diseases. To determine the mechanisms linking a proteolytic effect of human neutrophil elastase (HNE) and mucin overproduction, we examined the effects of HNE on MUC5AC mucin production in human airway epithelial (NCI-H292) cells. Stimulation with HNE for 5–30 min induced MUC5AC production 24 h later, which was prevented by HNE serine active site inhibitors, implicating a proteolytic effect of HNE. MUC5AC induction was preceded by epidermal growth factor receptor (EGFR) tyrosine phosphorylation and was prevented by selective EGFR tyrosine kinase inhibitors, implicating EGFR activation. HNE-induced MUC5AC production was inhibited by a neutralizing transforming growth factor-α (TGF-α, an EGFR ligand) antibody and by a neutralizing EGFR antibody but not by oxygen free radical scavengers, further implicating TGF-α and ligand-dependent EGFR activation in the response. HNE decreased pro-TGF-α in NCI-H292 cells and increased TGF-α in cell culture supernatant. From these results, we conclude that HNE-induced MUC5AC mucin production occurs via its proteolytic activation of an EGFR signaling cascade involving TGF-α.


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