scholarly journals Epidermal growth factor–stimulated Akt phosphorylation requires clathrin or ErbB2 but not receptor endocytosis

2015 ◽  
Vol 26 (19) ◽  
pp. 3504-3519 ◽  
Author(s):  
Camilo Garay ◽  
Gurjeet Judge ◽  
Stefanie Lucarelli ◽  
Stephen Bautista ◽  
Rohan Pandey ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Gene Silencing ◽  
Receptor Internalization ◽  
Membrane Structures ◽  
Coated Pits ◽  
Akt Phosphorylation ◽  
Erbb2 Expression ◽  
Epidermal Growth

Epidermal growth factor (EGF) binding to its receptor (EGFR) activates several signaling intermediates, including Akt, leading to control of cell survival and metabolism. Concomitantly, ligand-bound EGFR is incorporated into clathrin-coated pits—membrane structures containing clathrin and other proteins—eventually leading to receptor internalization. Whether clathrin might regulate EGFR signaling at the plasma membrane before vesicle scission is poorly understood. We compared the effect of clathrin perturbation (preventing formation of, or receptor recruitment to, clathrin structures) to that of dynamin2 (allowing formation of clathrin structures but preventing EGFR internalization) under conditions in which EGFR endocytosis is clathrin dependent. Clathrin perturbation by siRNA gene silencing, with the clathrin inhibitor pitstop2, or knocksideways silencing inhibited EGF-simulated Gab1 and Akt phosphorylation in ARPE-19 cells. In contrast, perturbation of dynamin2 with inhibitors or by siRNA gene silencing did not affect EGF-stimulated Gab1 or Akt phosphorylation. EGF stimulation enriched Gab1 and phospho-Gab1 within clathrin structures. ARPE-19 cells have low ErbB2 expression, and overexpression and knockdown experiments revealed that robust ErbB2 expression bypassed the requirement for clathrin for EGF-stimulated Akt phosphorylation. Thus clathrin scaffolds may represent unique plasma membrane signaling microdomains required for signaling by certain receptors, a function that can be separated from vesicle formation.

scholarly journals Clathrin and TOM1L1 regulate epidermal growth factor receptor signaling at the plasma membrane

2021 ◽  
Author(s):  
Gurjeet Singh Judge
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Intracellular Signaling ◽  
Fluorescent Labeling ◽  
Cell Physiology ◽  
Egfr Signaling ◽  
Coated Pits ◽  
Akt Phosphorylation ◽  
Epidermal Growth

Epidermal growth factor (EGF) receptor (EGFR) controls many aspects of cell physiology via the activation of intracellular signaling pathways. Aberrant EGFR signaling and overexpression of EGFR is a characteristic of various cancer types. Ligandbound EGFR elicits phosphorylation of Gab1, which activates phosphatidylinositol-3-kinase (PI3K), which in turn leads to Akt phosphorylation and activation. Akt is a central regulator of cell survival and metabolism. Rapidly upon binding EGF, the receptor is recruited to clathrin-coated pits (CCPs), eventually leading to EGFR endocytosis. As such, receptor-proximal EGFR signaling occurs while the receptor is enriched with CCPs at the plasma membrane. We have recently found that clathrin, but not receptor endocytosis, is required for EGF-stimulated phosphorylation of Akt, yet how clathrin controls EGFR signaling at the plasma membrane remains poorly understood. Clathrin interacts with and recruits numerous proteins to the plasma membrane. To examine how specific clathrin-interacting proteins may underlie the requirement for clathrin in EGFR signaling, I have examined the role of TOM1L1, which interacts with clathrin, EGFR and Src-family kinases (SFKs) through distinct domains. SiRNA gene silencing of TOM1L1 impairs EGF-stimulated Akt phosphorylation, as did expression of a dominant-interfering mutant of TOM1L1 deficient in clathrin binding. Using fluorescent labeling of clathrin, TOM1L1 and other signaling intermediates coupled to total internal reflection fluorescence microscopy; I found that CCPs are enriched in TOM1L1 and phosphorylated Gab1 upon EGF stimulation. These findings indicate that the clathrin-binding adaptor TOM1L1 regulates EGF-stimulated Akt phosphorylation, thus revealing a novel molecular mechanism of regulation of EGFR signaling at the plasma membrane.

scholarly journals Clathrin and TOM1L1 regulate epidermal growth factor receptor signaling at the plasma membrane

2021 ◽  
Author(s):  
Gurjeet Singh Judge
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Intracellular Signaling ◽  
Fluorescent Labeling ◽  
Cell Physiology ◽  
Egfr Signaling ◽  
Coated Pits ◽  
Akt Phosphorylation ◽  
Epidermal Growth

Epidermal growth factor (EGF) receptor (EGFR) controls many aspects of cell physiology via the activation of intracellular signaling pathways. Aberrant EGFR signaling and overexpression of EGFR is a characteristic of various cancer types. Ligandbound EGFR elicits phosphorylation of Gab1, which activates phosphatidylinositol-3-kinase (PI3K), which in turn leads to Akt phosphorylation and activation. Akt is a central regulator of cell survival and metabolism. Rapidly upon binding EGF, the receptor is recruited to clathrin-coated pits (CCPs), eventually leading to EGFR endocytosis. As such, receptor-proximal EGFR signaling occurs while the receptor is enriched with CCPs at the plasma membrane. We have recently found that clathrin, but not receptor endocytosis, is required for EGF-stimulated phosphorylation of Akt, yet how clathrin controls EGFR signaling at the plasma membrane remains poorly understood. Clathrin interacts with and recruits numerous proteins to the plasma membrane. To examine how specific clathrin-interacting proteins may underlie the requirement for clathrin in EGFR signaling, I have examined the role of TOM1L1, which interacts with clathrin, EGFR and Src-family kinases (SFKs) through distinct domains. SiRNA gene silencing of TOM1L1 impairs EGF-stimulated Akt phosphorylation, as did expression of a dominant-interfering mutant of TOM1L1 deficient in clathrin binding. Using fluorescent labeling of clathrin, TOM1L1 and other signaling intermediates coupled to total internal reflection fluorescence microscopy; I found that CCPs are enriched in TOM1L1 and phosphorylated Gab1 upon EGF stimulation. These findings indicate that the clathrin-binding adaptor TOM1L1 regulates EGF-stimulated Akt phosphorylation, thus revealing a novel molecular mechanism of regulation of EGFR signaling at the plasma membrane.

scholarly journals The Inhibitory Effect of ErbB2 on Epidermal Growth Factor-induced Formation of Clathrin-coated Pits Correlates with Retention of Epidermal Growth Factor Receptor-ErbB2 Oligomeric Complexes at the Plasma Membrane

2005 ◽  
Vol 16 (12) ◽  
pp. 5832-5842 ◽  
Author(s):  
Camilla Haslekås ◽  
Kamilla Breen ◽  
Ketil W. Pedersen ◽  
Lene E. Johannessen ◽  
Espen Stang ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Egf Receptor ◽  
Growth Factor Receptor ◽  
Inhibitory Effect ◽  
Coated Pits ◽  
Transfected Cells ◽  
Epidermal Growth

By constructing stably transfected cells harboring the same amount of epidermal growth factor (EGF) receptor (EGFR), but with increasing overexpression of ErbB2, we have demonstrated that ErbB2 efficiently inhibits internalization of ligand-bound EGFR. Apparently, ErbB2 inhibits internalization of EGF-bound EGFR by constitutively driving EGFR-ErbB2 hetero/oligomerization. We have demonstrated that ErbB2 does not inhibit phosphorylation or ubiquitination of the EGFR. Our data further indicate that the endocytosis deficiency of ErbB2 and of EGFR-ErbB2 heterodimers/oligomers cannot be explained by anchoring of ErbB2 to PDZ-containing proteins such as Erbin. Instead, we demonstrate that in contrast to EGFR homodimers, which are capable of inducing new clathrin-coated pits in serum-starved cells upon incubation with EGF, clathrin-coated pits are not induced upon activation of EGFR-ErbB2 heterodimers/oligomers.

scholarly journals Eps15 Is Recruited to the Plasma Membrane upon Epidermal Growth Factor Receptor Activation and Localizes to Components of the Endocytic Pathway during Receptor Internalization

1999 ◽  
Vol 10 (2) ◽  
pp. 417-434 ◽  
Author(s):  
Maria Rosaria Torrisi ◽  
Lavinia Vittoria Lotti ◽  
Francesca Belleudi ◽  
Roberto Gradini ◽  
Anna Elisabetta Salcini ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Receptor Activation ◽  
Endocytic Pathway ◽  
Receptor Internalization ◽  
Epidermal Growth

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.

scholarly journals Regulation of epidermal growth factor receptor signaling by clathrin-coated membrane microdomains

2021 ◽  
Author(s):  
Camilo Garay
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinases ◽  
Egf Receptor ◽  
Akt Signaling ◽  
Membrane Microdomains ◽  
Egfr Signaling ◽  
Coated Pits ◽  
Akt Phosphorylation ◽  
Epidermal Growth

The phosphatidylinositol-3-kinase (PI3K)-Akt signaling axis controls cell survival, proliferation and metabolism, and is activated by receptor tyrosine kinases (RTKs) such as the epidermal growth factor (EGF) receptor (EGFR). In addition to activation of PI3K-Akt signaling, the binding of EGF to its receptor results in rapid recruitment of EGFR to clathrin-coated pits (CCPs) followed by eventual EGFR internalization. Hence, receptor-proximal activation of signaling intermediates occurs while EGFR resides within CCPs; however, whether CCPs are required for EGFR signaling remains poorly understood. Using a combination of pharmacological inhibition and siRNA gene silencing of clathrin, we have examined how clathrin controls EGF-stimulated activation of Akt. We find that perturbation of clathrin, but not of EGFR endocytosis by perturbation of dynamin leads to disruption of EGF-stimulated Akt phosphorylation. This indicates that clathrin acts in a function separate from its role in endocytosis to regulate EGFR signaling at the plasma membrane. The EGF-stimulated phosphorylation of the signaling intermediate Gab1, but not that of EGFR itself, was also abrogated upon disruption of clathrin. We then utilized total internal reflection fluorescence microscopy (TIRF-M) to examine the hierarchy of recruitment of EGFR signaling components to CCPs. Collectively, these findings suggest a role for clathrin as a central regulator of EGFR signaling leading to Gab1 and Akt phosphorylation.

Clathrin, adaptors and eps15 in endosomes containing activated epidermal growth factor receptors

1999 ◽  
Vol 112 (3) ◽  
pp. 317-327 ◽  
Author(s):  
T. Sorkina ◽  
A. Bild ◽  
F. Tebar ◽  
A. Sorkin
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Adaptor Protein ◽  
Receptor Internalization ◽  
Image Deconvolution ◽  
Protein Markers ◽  
Coated Pits ◽  
Early Endosomes ◽  
Epidermal Growth ◽  
Clathrin Adaptor

Activation of the epidermal growth factor receptor (EGFR) by EGF results in binding of clathrin adaptor protein complex AP-2 to the receptor cytoplasmic tail. The transient interaction with AP-2 is thought to be responsible for the selective recruitment of the EGFR into coated pits during endocytosis. In this study we found that EGF-induced EGFR/AP-2 association, measured by co-immunoprecipitation, persists after receptor internalization. Double-label immunofluorescence of EGF-treated A-431 and COS-1 cells revealed the presence of AP-2, clathrin and eps15, another component of the plasma membrane coated pits, in the large perinuclear endosomes loaded with EGFRs. By optical sectioning and image deconvolution, the immunoreactivities were seen to be distributed within vesicular and tubular elements of these endosomes. In addition, these compartments contained the transferrin receptors and a EEA.1 protein, markers of early endosomes. Furthermore, Golgi clathrin adaptor complex AP-1 was found in EGFR-containing endosomes and EGFR immunoprecipitates in A-431 cells. The direct interaction of the EGFR with micro1 as well as micro2 subunits of AP-1 and AP-2, correspondingly, was shown using the yeast two-hybrid assay. Brefeldin A, a drug that releases AP-1 from the trans-Golgi membranes, had no effect on AP-1 association with endosomes and its co-precipitation with EGFR. Taken together, the data suggest that endosomal EGFR-AP complexes make up a significant portion of the total amount of these complexes detectable by co-immunoprecipitation. It can be proposed that APs are capable of binding to the endosomal membrane via a mechanism that requires AP interaction with the intracellular tails of multimeric receptors like activated EGFR, which in turn allows recruitment of clathrin and eps15. The hypothesis that the competition between adaptor complexes for binding to the receptor tails in endosomes may regulate of the sorting of receptors is discussed.

scholarly journals Transit of epidermal growth factor through coated pits of the Golgi system.

1982 ◽  
Vol 94 (1) ◽  
pp. 207-212 ◽  
Author(s):  
M C Willingham ◽  
I H Pastan
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Carcinoma Cells ◽  
Coated Pits ◽  
Human Carcinoma ◽  
Golgi System ◽  
Reticular System ◽  
Entire Cell ◽  
Epidermal Growth

Using the direct conjugate of epidermal growth factor (EGF) and horseradish peroxidase, we have followed the entry of EGF into KB (human carcinoma) cells. EGF initially was found bound diffusely to the entire cell surface at 4 degrees C; on warming to 37 degrees C, EGF was found clustered in clathrin-coated pits on the plasma membrane in 1 min or less. Within 1-2 min at 37 degrees C, EGF began to accumulate in receptosomes within the cell and remained there for up to 10 min. At 10-13 min after warming to 37 degrees C, EGF was found in thin reticular membranous elements of the Golgi system, as well as concentrated in the clathrin-coated pits present on these membranes. By 15 min after warming, EGF began to be delivered to lysosomes located near the Golgi system. These findings suggest that clathrin-coated pits in the Golgi reticular system accumulate EGF before delivery to lysosomes.

scholarly journals Regulation of epidermal growth factor receptor signaling by clathrin-coated membrane microdomains

2021 ◽  
Author(s):  
Camilo Garay
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinases ◽  
Egf Receptor ◽  
Akt Signaling ◽  
Membrane Microdomains ◽  
Egfr Signaling ◽  
Coated Pits ◽  
Akt Phosphorylation ◽  
Epidermal Growth

The phosphatidylinositol-3-kinase (PI3K)-Akt signaling axis controls cell survival, proliferation and metabolism, and is activated by receptor tyrosine kinases (RTKs) such as the epidermal growth factor (EGF) receptor (EGFR). In addition to activation of PI3K-Akt signaling, the binding of EGF to its receptor results in rapid recruitment of EGFR to clathrin-coated pits (CCPs) followed by eventual EGFR internalization. Hence, receptor-proximal activation of signaling intermediates occurs while EGFR resides within CCPs; however, whether CCPs are required for EGFR signaling remains poorly understood. Using a combination of pharmacological inhibition and siRNA gene silencing of clathrin, we have examined how clathrin controls EGF-stimulated activation of Akt. We find that perturbation of clathrin, but not of EGFR endocytosis by perturbation of dynamin leads to disruption of EGF-stimulated Akt phosphorylation. This indicates that clathrin acts in a function separate from its role in endocytosis to regulate EGFR signaling at the plasma membrane. The EGF-stimulated phosphorylation of the signaling intermediate Gab1, but not that of EGFR itself, was also abrogated upon disruption of clathrin. We then utilized total internal reflection fluorescence microscopy (TIRF-M) to examine the hierarchy of recruitment of EGFR signaling components to CCPs. Collectively, these findings suggest a role for clathrin as a central regulator of EGFR signaling leading to Gab1 and Akt phosphorylation.

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