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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The epidermal growth factor (EGF) receptor (EGFR) plays a central role in regulating cell proliferation, differentiation, and migration. Cellular responses to EGF are dependent upon the amount of EGFR present on the cell surface. Stimulation with EGF induces sequestration of the receptor from the plasma membrane and its subsequent downregulation. Recently, internalization of the EGFR was also shown to be required for mitogenic signaling via the activation of MAP kinases. Therefore, mechanisms regulating internalization of the EGFR represent an important facet for the control of cellular response. Here, we demonstrate that EGFR is removed from the cell surface not only following stimulation with EGF, but also in response to stimulation of G protein-coupled lysophosphatidic acid (LPA) and beta2 adrenergic (beta2AR) receptors. Using a FLAG epitope-tagged EGFR to quantitate receptor internalization, we show that incubation with EGF, LPA, or isoproterenol (ISO) causes the time-dependent loss of cell surface EGFR. Internalization of EGFR by these ligands involves the tyrosine kinase activity of the receptor itself and c-Src, as well as the GTPase activity of dynamin. Unexpectedly, we find that internalization of the EGFR by EGF is dependent upon Gbetagamma and beta-arrestin proteins; expression of minigenes encoding the carboxyl terminii of the G protein-coupled receptor kinase 2, or beta-arrestin1, attenuates LPA-, ISO-, and EGF-mediated internalization of EGFR. Thus, G protein-coupled receptors can control the function of the EGFR by regulating its endocytosis.
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PMID:Regulation of epidermal growth factor receptor internalization by G protein-coupled receptors. 1262 54

Phospholipase C-gamma1 (PLC-gamma1), which interacts with a variety of signaling molecules through its two Src homology (SH) 2 domains and a single SH3 domain has been implicated in the regulation of many cellular functions. We demonstrate that PLC-gamma1 acts as a guanine nucleotide exchange factor (GEF) of dynamin-1, a 100 kDa GTPase protein, which is involved in clathrin-mediated endocytosis of epidermal growth factor (EGF) receptor. Overexpression of PLC-gamma1 increases endocytosis of the EGF receptor by increasing guanine nucleotide exchange activity of dynamin-1. The GEF activity of PLC-gamma1 is mediated by the direct interaction of its SH3 domain with dynamin-1. EGF-dependent activation of ERK and serum response element (SRE) are both up-regulated in PC12 cells stably overexpressing PLC-gamma1, but knockdown of PLC-gamma1 by siRNA significantly reduces ERK activation. These results establish a new role for PLC-gamma1 in the regulation of endocytosis and suggest that endocytosis of activated EGF receptors may mediate PLC-gamma1-dependent proliferation.
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PMID:Phospholipase C-gamma1 is a guanine nucleotide exchange factor for dynamin-1 and enhances dynamin-1-dependent epidermal growth factor receptor endocytosis. 1525 17

The biological function of receptors is determined by their appropriate trafficking through the endosomal pathway. Following internalization, the transferrin (Tf) receptor quantitatively recycles to the plasma membrane, whereas the epidermal growth factor (EGF) receptor undergoes degradation. To determine how Tf and EGF engage these two different pathways we imaged their binding and early endocytic pathway in live cells using total internal reflection fluorescence microscopy (TIRF-M). We find that EGF and Tf bind to distinct plasma membrane regions and are incorporated into different endocytic vesicles. After internalization, both EGF-enriched and Tf-enriched vesicles interact with endosomes containing early endosome antigen 1 (EEA1). EGF is incorporated and retained in these endosomes, while Tf-containing vesicles rapidly dissociate and move to a juxtanuclear compartment. Endocytic vesicles carrying EGF recruit more Rab5 GTPase than those carrying Tf, which, by strengthening their association with EEA1-enriched endosomes, may provide a mechanism for the observed cargo-specific sorting. These results reveal pre-endocytic sorting of Tf and EGF, a specialized role for EEA1-enriched endosomes in EGF trafficking, and a potential mechanism for cargo-specified sorting of endocytic vesicles by these endosomes.
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PMID:Sorting of EGF and transferrin at the plasma membrane and by cargo-specific signaling to EEA1-enriched endosomes. 1882 13

The development of personalized medicine with a focus on novel targeted therapies has supplanted the one-size-fits-all approach to the treatment of many cancers, including non-small cell lung cancer. Targeted therapies, if given to a patient subpopulation enriched by the presence of relevant molecular targets, can often abrogate cell signaling that perpetuates cancer progression. Critical targets activating procancer pathways include, but are not limited to, epidermal growth factor receptor (EGFR), hepatocyte growth factor receptor (MET), vascular endothelial growth factor (VEGF), VEGF receptor, GTPase KRAS (KRAS), receptor tyrosine protein kinase erbB-2 (HER2), echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA), serine/threonine-protein kinase B-raf (BRAF), and insulin-like growth factor 1 receptor (IGF-1R). Some target-directed therapies, such as epidermal growth factor receptor tyrosine kinase inhibitors and anti-VEGF monoclonal antibody, have already been approved for clinical use. Others, such as those targeted to MET, VEGFR, HER2, PIK3CA, and IGF-1R, are in clinical testing. This review describes molecular targets in non-small cell lung cancer that are in development or being clinically applied and their implications for developing novel anticancer therapies for this previously refractory malignancy.
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PMID:Novel therapeutic targets in non-small cell lung cancer. 2184 57


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