Identification of a new regulation pathway of EGFR and E-cadherin dynamics
This article has been Reviewed by the following groups
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
- Evaluated articles (eLife)
Abstract
EGFR plays key roles in multiple cellular processes such as cell differentiation, cell proliferation, migration and epithelia homeostasis. Phosphorylation of the receptor, intracellular signaling and trafficking are major events regulating EGFR functions. Galectin-7, a soluble lectin expressed in epithelia such as the skin, has been shown to be involved in cell differentiation. Through this study we demonstrate that galectin-7 regulates EGFR function by a direct interaction with its extracellular domain hence modifying its downstream signaling and endocytic pathway. From observations in mice we focused on the molecular mechanisms deciphering the glycosylation dependent interaction between EGFR and galectin-7. Interestingly, we also revealed that galectin-7 is a direct binder of both EGFR and E-cadherin bridging them together. Strikingly this study not only deciphers a new molecular mechanism of EGFR regulation but also points out a novel molecular interaction between EGFR and E-cadherin, two major regulators of the balance between proliferation and differentiation.
SUMMARY
EGFR and E-cadherin are known to interact and to regulate epithelial homeostasis. In this study we unravel in the epidermis a new partner and regulator of EGFR which also binds E-cadherin reciprocally bridging their dynamics and functions.
Article activity feed
-
###Reviewer #2:
In this manuscript, the authors describe an interaction of EGFR and Gal7 and that Gal7 binding downregulates EGFR activity. They show that Gal7 null mice exhibit thickening of the epidermis. In the absence of Gal7, EGFR is more active, which is supported by increased EGFR phosphorylation and phosphorylation of downstream molecules. Although a related protein, Gal3, has been shown to upregulate EGFR activity that may be functionally relevant in colorectal cancer, the authors' description of EGFR-Gal7 interaction is new. However, a number of claims made are not supported by the data presented. For example, in the abstract, the authors state that Gal7 is a direct binder of E-cadherin but it is not demonstrated experimentally.
Additional comments:
In Figure 3A graphs, authors show that both baseline (Fig. 3A) and …
###Reviewer #2:
In this manuscript, the authors describe an interaction of EGFR and Gal7 and that Gal7 binding downregulates EGFR activity. They show that Gal7 null mice exhibit thickening of the epidermis. In the absence of Gal7, EGFR is more active, which is supported by increased EGFR phosphorylation and phosphorylation of downstream molecules. Although a related protein, Gal3, has been shown to upregulate EGFR activity that may be functionally relevant in colorectal cancer, the authors' description of EGFR-Gal7 interaction is new. However, a number of claims made are not supported by the data presented. For example, in the abstract, the authors state that Gal7 is a direct binder of E-cadherin but it is not demonstrated experimentally.
Additional comments:
In Figure 3A graphs, authors show that both baseline (Fig. 3A) and ligand-induced (Fig. 3B) EGFR phosphorylation is higher in Gal7 knockdown cells. This reviewer is left to assume that Figure 3A graphs are derived from WB data from Figure 3B and in those WBs the increase in pEGFR, pERK, pAKT levels after Gal7 in absence of EGFR are not convincing. Also, Fig. 3B has two panels and they are not clearly explained in the figure legend.
Figure 4A, lower panels would be more convincing if HaCaT and shGal7 were run on same gel, just like upper panels.
Figure 4B, on top of WB panels, labels are not aligned properly and the reviewer is left to assume that the loading conditions are 0, 0.5, 1, 2, 4, 8, and 24 h, first for HaCaT, followed by same time points for shGal7. Also, the results from time course in Figure 4A and 4B are not consistent; total EGFR levels are downregulated as early as 2 min in Fig. 4A, whereas loss of EGFR is more gradual (over hours) in Figure 4B.
In Figure 4B legend, cycloheximide treatment is mentioned but in the figure it is not indicated which samples are treated with cycloheximide.
5)In Figure 7A, +EGF+rGal7 condition should be included for shGal7 cells
Figure 7F experiment needs to be on the same blot. Also, independent binding of Gal7 with E-cadherin is not shown in Fig. 7F or a similar experiment. This might indicate that both EGFR and Gal7 cooperate to stabilize interaction with E-cadherin as E-cadherin is unable to bind to either individually.
Figure 7 is referred to as Figure 8 in the text.
The manuscript is not well-written and needs to be thoroughly edited. For example, page 8, last line. “Colocalization assays of Gal7 and LAMP-1 gave no results”.
-
###Reviewer #1:
In this paper the authors provide evidence that Galectin-7 binds the extracellular domain of EGFR regulating its signaling.
Although the in vitro study is for the most part nicely done, the major problem of this paper is the overall novelty. To this end several publications clearly show that, 1) members of the galectin family (e.g. 3) regulate EGF receptor signaling; 2) galectins (e.g. 8) regulate the early trafficking of EGFR; 3) galectins (e.g. 3) binds and regulate RTKs, including EGFR; 4) galectin-7, the topic of this paper, regulates e-cadherin expression and dynamics. Thus it is felt that the fact that galectin-7 binds to and regulates EGFR signaling is not sufficiently novel.
In addition, it is felt that some experiments are not sufficiently quantified (e.g. intracellular signaling) and some data are of …
###Reviewer #1:
In this paper the authors provide evidence that Galectin-7 binds the extracellular domain of EGFR regulating its signaling.
Although the in vitro study is for the most part nicely done, the major problem of this paper is the overall novelty. To this end several publications clearly show that, 1) members of the galectin family (e.g. 3) regulate EGF receptor signaling; 2) galectins (e.g. 8) regulate the early trafficking of EGFR; 3) galectins (e.g. 3) binds and regulate RTKs, including EGFR; 4) galectin-7, the topic of this paper, regulates e-cadherin expression and dynamics. Thus it is felt that the fact that galectin-7 binds to and regulates EGFR signaling is not sufficiently novel.
In addition, it is felt that some experiments are not sufficiently quantified (e.g. intracellular signaling) and some data are of descriptive nature (e.g. the characterization of the gal-7 null mice and in vivo evidence that gal-7 interacts with EGFR is somehow superficial).
-
##Preprint Review
This preprint was reviewed using eLife’s Preprint Review service, which provides public peer reviews of manuscripts posted on bioRxiv for the benefit of the authors, readers, potential readers, and others interested in our assessment of the work. This review applies only to version 1 of the manuscript.
###Summary:
As you can see from the reviews included, the reviewers have identified major shortcomings with this study that overall dampen the enthusiasm for the results reported. One of the major pitfalls identified is the overall novelty of the paper. As you can see from the detailed comments by the reviewers, other Gal family members have been shown to regulate EGF activation and trafficking, and to bind RTKs. Thus the identification of Gal 7 as a novel regulator of EGF receptors does not provide a clear advance. In …
##Preprint Review
This preprint was reviewed using eLife’s Preprint Review service, which provides public peer reviews of manuscripts posted on bioRxiv for the benefit of the authors, readers, potential readers, and others interested in our assessment of the work. This review applies only to version 1 of the manuscript.
###Summary:
As you can see from the reviews included, the reviewers have identified major shortcomings with this study that overall dampen the enthusiasm for the results reported. One of the major pitfalls identified is the overall novelty of the paper. As you can see from the detailed comments by the reviewers, other Gal family members have been shown to regulate EGF activation and trafficking, and to bind RTKs. Thus the identification of Gal 7 as a novel regulator of EGF receptors does not provide a clear advance. In addition, the claim that Gal7 is a direct binder of E-cadherin is not demonstrated experimentally. Some experiments shown should be shown on the same blots, and it felt that they lack solid quantification and in some cases are of descriptive nature. Finally it is felt that the manuscript is not well written and editing is recommended.
-
