The chemical synthesis and binding affinity to the EGF receptor of the EGF-like domain of heparin-binding EGF-like growth factor (HB-EGF)

2003 ◽  
Vol 9 (4) ◽  
pp. 244-250 ◽  
Author(s):  
Song Yub Shin ◽  
Tetsuo Yokoyama ◽  
Takato Takenouchi ◽  
Eisuke Munekata
2005 ◽  
Vol 16 (6) ◽  
pp. 2984-2998 ◽  
Author(s):  
Jianying Dong ◽  
Lee K. Opresko ◽  
William Chrisler ◽  
Galya Orr ◽  
Ryan D. Quesenberry ◽  
...  

All ligands of the epidermal growth factor (EGF) receptor (EGFR) are synthesized as membrane-anchored precursors. Previous work has suggested that some ligands, such as EGF, must be proteolytically released to be active, whereas others, such as heparin-binding EGF-like growth factor (HB-EGF) can function while still anchored to the membrane (i.e., juxtacrine signaling). To explore the structural basis for these differences in ligand activity, we engineered a series of membrane-anchored ligands in which the core, receptor-binding domain of EGF was combined with different domains of both EGF and HB-EGF. We found that ligands having the N-terminal extension of EGF could not bind to the EGFR, even when released from the membrane. Ligands lacking an N-terminal extension, but possessing the membrane-anchoring domain of EGF, still required proteolytic release for activity, whereas ligands with the membrane-anchoring domain of HB-EGF could elicit full biological activity while still membrane anchored. Ligands containing the HB-EGF membrane anchor, but lacking an N-terminal extension, activated EGFR during their transit through the Golgi apparatus. However, cell-mixing experiments and fluorescence resonance energy transfer studies showed that juxtacrine signaling typically occurred in trans at the cell surface, at points of cell-cell contact. Our data suggest that the membrane-anchoring domain of ligands selectively controls their ability to participate in juxtacrine signaling and thus, only a subclass of EGFR ligands can act in a juxtacrine mode.


2008 ◽  
Vol 294 (3) ◽  
pp. F459-F468 ◽  
Author(s):  
Shougang Zhuang ◽  
Gilbert R. Kinsey ◽  
Kyle Rasbach ◽  
Rick G. Schnellmann

Our recent studies have shown that proliferation of renal proximal tubular cells (RPTC) in the absence of growth factors requires activation of the epidermal growth factor (EGF) receptor. We sought to identify the endogenous EGF receptor ligand and investigate the mechanism(s) by which RPTC proliferate in different models. RPTC expressed both pro- and cleaved forms of heparin-binding epidermal growth factor (HB-EGF) and several metalloproteinases (MMP-2, -3, -9, and ADAM10, ADAM17) that have been reported to cleave HB-EGF. Treatment of RPTC with CRM 197, an inhibitor of HB-EGF binding to the EGF receptor, or downregulation of HB-EGF with small interfering RNA inhibited RPTC proliferation following plating. Furthermore, GM6001 (pan-MMP inhibitor), tumor-necrosis factor protease inhibitor-1 (TAPI-1; MMP and ADAM17 inhibitor), and GW280264X (ADAM10 and -17 inhibitor), but not GI254023X (ADAM10 inhibitor), attenuated the proliferation after plating. Although EGF receptor activation is required for RPTC proliferation after oxidant injury, CRM197, GM6001, and TAPI-1 did not block this response. In contrast, inhibition of Src with PP1 blocked EGF receptor activation and RPTC proliferation after oxidant injury. In addition, PP1 treatment attenuated HB-EGF-enhanced RPTC proliferation. We suggest that RPTC proliferation after plating is mediated by HB-EGF produced through an autocrine/paracrine mechanism and RPTC proliferation following oxidant injury is mediated by Src without involvement of HB-EGF.


2004 ◽  
Vol 286 (6) ◽  
pp. G992-G999 ◽  
Author(s):  
Natalie F. Sinclair ◽  
Wandong Ai ◽  
Raktima Raychowdhury ◽  
Meixia Bi ◽  
Timothy C. Wang ◽  
...  

Gastrin is a known growth/differentiation factor for the gastric mucosa. Its effects are likely mediated by the induction of heparin-binding epidermal-like growth factor (HB-EGF), a member of the EGF family of growth factors that is expressed by gastric parietal cells. In this study, we investigated the regulation of the HB-EGF promoter by gastrin in a human gastric cancer cell line. Serial human HB-EGF promoter-luciferase reporter deletion constructs and heterologous promoter constructs were transfected into AGS-E cells and stimulated with gastrin (10−7M) with or without various signal transduction inhibitors. EMSA were also performed. Gastrin stimulation resulted in a fivefold increase in HB-EGF-luciferase activity. The cis-acting element mediating gastrin responsiveness was mapped to the −69 to −58 region of the HB-EGF promoter. Gastrin stimulation was PKC dependent and at least partially mediated by activation of the EGF receptor.


1988 ◽  
Vol 8 (6) ◽  
pp. 2302-2308
Author(s):  
E Livneh ◽  
T J Dull ◽  
E Berent ◽  
R Prywes ◽  
A Ullrich ◽  
...  

The tumor promoter phorbol ester (TPA) modulates the binding affinity and the mitogenic capacity of the epidermal growth factor (EGF) receptor. Moreover, TPA-induced kinase C phosphorylation occurs mainly on Thr-654 of the EGF receptor, suggesting that the phosphorylation state of this residue regulates ligand-binding affinity and kinase activity of the EGF receptor. To examine the role of this residue, we prepared a Tyr-654 EGF receptor cDNA construct by in vitro site-directed mutagenesis. Like the wild-type receptor, the mutant receptor exhibited typical high- and low-affinity binding sites when expressed on the surface of NIH 3T3 cells. Moreover, TPA regulated the affinity of both wild-type and mutant receptors and stimulated receptor phosphorylation of serine and threonine residues other than Thr-654. The addition of TPA to NIH 3T3 cells expressing a wild-type human EGF receptor blocked the mitogenic capacity of EGF. However, this inhibition did not occur in cells expressing the Tyr-654 EGF receptor mutant. In the latter cells, EGF was able to stimulate DNA synthesis even in the presence of inhibitory concentrations of TPA. While phosphorylation of sites other than Thr-654 may regulate ligand-binding affinity, the phosphorylation of Thr-654 by kinase C appears to provide a negative control mechanism for EGF-induced mitogenesis in mouse NIH 3T3 fibroblasts.


2013 ◽  
Vol 201 (2) ◽  
pp. 279-292 ◽  
Author(s):  
Begoña Díaz ◽  
Angela Yuen ◽  
Shinji Iizuka ◽  
Shigeki Higashiyama ◽  
Sara A. Courtneidge

Notch regulates cell–cell contact-dependent signaling and is activated by hypoxia, a microenvironmental condition that promotes cellular invasion during both normal physiology and disease. The mechanisms by which hypoxia and Notch regulate cellular invasion are not fully elucidated. In this paper, we show that, in cancer cells, hypoxia increased the levels and activity of the ADAM12 metalloprotease in a Notch signaling–dependent manner, leading to increased ectodomain shedding of the epidermal growth factor (EGF) receptor (EGFR) ligand heparin-binding EGF-like growth factor. Released HB-EGF induced the formation of invadopodia, cellular structures that aid cancer cell invasion. Thus, we describe a signaling pathway that couples cell contact–dependent signaling with the paracrine activation of the EGFR, indicating cross talk between the Notch and EGFR pathways in promoting cancer cell invasion. This signaling pathway might regulate the coordinated acquisition of invasiveness by neighboring cells and mediate the communication between normoxic and hypoxic areas of tumors to facilitate cancer cell invasion.


2007 ◽  
Vol 18 (11) ◽  
pp. 4446-4456 ◽  
Author(s):  
Fenghua Zeng ◽  
Ming-Zhi Zhang ◽  
Amar B. Singh ◽  
Roy Zent ◽  
Raymond C. Harris

ErbB4, a member of the epidermal growth factor (EGF) receptor family that can be activated by heregulin β1 and heparin binding (HB)-EGF, is expressed as alternatively spliced isoforms characterized by variant extracellular juxtamembrane (JM) and intracellular cytoplasmic (CYT) domains. ErbB4 plays a critical role in cardiac and neural development. We demonstrated that ErbB4 is expressed in the ureteric buds and developing tubules of embryonic rat kidney and in collecting ducts in adult. The predominant isoforms expressed in kidney are JM-a and CYT-2. In ErbB4-transfected MDCK II cells, basal cell proliferation and hepatocyte growth factor (HGF)-induced tubule formation were decreased by all four isoforms. Only JM-a/CYT-2 cells formed tubules upon HB-EGF stimulation. ErbB4 was activated by both HRG-β1 and HB-EGF stimulation; however, compared with HRG-β1, HB-EGF induced phosphorylation of the 80-kDa cytoplasmic cleavage fragment of the JM-a/CYT-2 isoform. HB-EGF also induced early activation of ERK1/2 in JM-a/CYT-2 cells and promoted nuclear translocation of the JM-a/CYT-2 cytoplasmic tail. In summary, our data indicate that JM-a/CYT-2, the ErbB4 isoform that is proteinase cleavable but does not contain a PI3K-binding domain in its cytoplasmic tail, mediates important functions in renal epithelial cells in response to HB-EGF.


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