FAK–MAPK‐dependent adhesion disassembly downstream of L1 contributes to semaphorin3A‐induced collapse

Abstract

The editors contacted the authors after becoming aware of potential image aberrations in the paper. Based on the exchanges with the authors, a reassessment of key figures by an external referee and internal analysis at the Journal, the editors correct the following figures and associated claims, and publish the available source data with this notice:

Figure 3B and G are retracted and replaced.

Figure 3B and G. Original.

 

Figure 3C is retracted.

Figure 3B and G. Corrected.

 

Figure 4A is corrected after identification of an error.

Figure 4A. Original.

 

Splice sites were identified and source data are published, where available, for Figs 3A, D and E, and 4C.

Figure legend for Figs 2E and 4A is updated.

Figure 4A. Corrected.

 

Journal Statement.

Figure 3B and G

The Erk 1/2 blots in Fig 3B and G are duplicated. The authors agree that the blots are duplicated, and note that they made an error in the assembly of the figure panels. The author has provided source data, which is consistent with the original published figure. We are retracting and replacing the Erk 1/2 figure panels.

Figure 3C

After concluding an internal analysis of the figure set, a splice site in Fig 3C was detected. Source data were provided by the authors; the editors noted discrepancies between the provided source data and Fig 3C. The provided data revealed that in contrast to what is shown in Fig 3C, L1 is not detectable when expressing the L1‐1146 mutant. Due to this discrepancy, we are herewith retracting Fig 3C and the respective legend along with the reported conclusion that FAK signaling is required for MAPK activation in response to SEMA3A. We are also retracting the model shown in Fig 8Ad and associated text statement:

“Second, cells were transfected with Nrp1 and L1‐1146 mutants lacking FAK recruitment, and in this condition, Sema3A‐induced erk phosphorylation was also abrogated (Figure 3C).”

The editors note that the L1‐1146 mutant is used in Figs 4B and 5B and C and that, in these experiments, there is no control provided that L1 is expressed. A control for L1 expression is displayed in Fig 3F.

Figure 4A

The editors were made aware of a duplication in Fig 4A. After discussion with the authors and an internal analysis of the final submitted manuscript files, the editors note that a duplication in Fig 4A was not present in the accepted manuscript figure set. In the absence of archived manuscript proofs, the cause of this duplication remains unclear. The editors can confirm that the accepted data in Fig 4A raise no image integrity concerns. Figure 4A is retracted and replaced with the original accepted Fig 4A.

Figure 2B and C

The editors were made aware of a potential duplication in the Fig 2B Nrpl/plex^VSV and Fig 2C plex^VSV, IP L1 western blots. After analyzing the published figure and the provided author source data, the editors concluded that there is no definitive evidence for an image aberration. The authors provided source data that are published with this corrigendum.

Splice Sites

Figures 3A, D and E, and 4C

Multiple splice sites were detected, which were not marked in the published manuscript. The authors provided the editors with source data where available. These data are published alongside the corrigendum. In our assessment, these source data are consistent with the source data provided. Other splice sites were detected in the figures but are identifiable by the clear spacing between blots.

Figure legend.

Figure legend description for Fig 2E is updated from:

Sema3A induces FAK autophosphorylation detected with anti‐py397 in cells expressing L1/Nrp1 but not Nrp1/Plex^VSV or Plex^VSV. None of the Plexin‐A2‐A3‐A4 /Nrp1 complexes mediate FAK phosphorylation upon Sema3A stimulation.

To (changes in bold).

Sema3A induces FAK autophosphorylation detected with anti‐py397 in cells expressing L1/Nrp1 but not Nrp1/Plex^VSV or Plex^VSV. None of the Plexin‐A2‐A3‐A4/Nrp1 complexes mediate FAK phosphorylation upon Sema3A stimulation. The L1/NrPp1 samples have been used as control for both panel 2E and panel 4A.

Figure legend for Fig 4A is updated from:

The L1 ser mutations 1194 and 1224 abolished the Sema3A‐induced Erk1/2 phosphorylation in L1/Nrp1‐expressing cells. Y397 FAK phosphorylation is still detected in cells expressing complexes of Nrp1 and L1_S1194L and L1_S1224L.

To (changes in bold).

The L1 ser mutations 1194 and 1224 abolished the Sema3A‐induced Erk1/2 phosphorylation in L1/Nrp1‐expressing cells. Y397 FAK phosphorylation is still detected in cells expressing complexes of Nrp1 and L1_S1194L and L1_S1224L. The L1/NrPp1 samples have been used as control for both panel 2E and panel 4A.

Author Statement.

Author Contribution Section

The paper did not contain a detailed author contribution section, and for transparency and completeness, we add this information here.

A. Bechara, H. Nawabi, M. Bozon, K. Abouzid achieved all the Western blot experiments presented in the study. A. Bechara, H. Nawabi, F. Moret, and M. Bozon made all the culture experiments, the immunofluorescence labeling, and analysis of the signal. M. Bozon performed the immunohistochemistry on brain sections from Plexin and L1 mutant mouse models (Fig 7).

Jun‐Lin Guan generated the FAK constructs used in the study. Avraham Yaron and Marc Tessier‐Lavigne generated the Plexin mouse models whose phenotypes were analyzed in the study (Fig 7). Vance Lemmon generated truncated L1 proteins, anti‐L1 antibody, and L1 knockout mouse model used in the study.

V. Castellani designed, supervised the study, and wrote the manuscript. A Bechara contributed to manuscript writing. Marc Tessier‐Lavigne and Vance Lemmon contributed to discussions and manuscript writing revision.

Figure 3B and G

The Erk1/2 panels for Fig 3B and G are derived from one contiguous experiment; thus, the same Erk1/2 control (L1/Nrp1/egfp) was used in both figure panels. When assembling Fig 3B and G, the panels were inadvertently mislabeled. This may have happened because the panels were differently organized:

1. The control pair was presented in the right for panel B but in the left for panel G.

2. The two Sema3A and control treatments that are compared within each pair of samples were presented in an inverted order: for panel B, it was Sema3A and control from left to right; for panel G, it was control and Sema3A3A from left to right.

Figure 3C

The figure showed the immunodetection of L1 proteins. The L1‐1146 mutant form was much more difficult to detect than the wild‐type form. We could detect the mutant protein after 1 h exposure but not after 1 min exposure as for the wild‐type protein. Thus, Fig 3C of the manuscript presented the detection of L1 and L1‐1146 proteins as a composite of both exposure times. The difference of detection could be due to modifications in stability or conformation, diminishing the recognition of the mutant protein by the antibody. The use of different batches of antibody (that were in addition reutilized for several western blots) could explain why in some experiments like in Fig 3F, we could detect the L1‐1146 form and much less or not in other experiments. Despite the difficulty of detection in Western blot, the expression of L1‐1146 had an impact on the behavior of cultured cells and downstream signaling after exposure to Sema3A. This was in agreement with Cheng et al (2005) reporting that the expression of this truncated protein altered neurite growth and branch formation.

Reference: Cheng L, Itoh K, Lemmon V (2005) L1‐mediated branching is regulated by two ezrin‐radixin‐moesin (ERM)‐binding sites, the RSLE region and a novel juxtamembrane ERM‐binding region. J Neurosci 25: 395–403

We are truly sorry about the errors when assembling the figures. We hope that our explanations and data from original blots convincingly show that none of the identified mistakes were made to manipulate the scientific conclusions and that these errors bring no benefit or different interpretation of the data. Our analyses were conducted on the original blots and are consistent with the conclusions of the study.

The authors apologize for these errors and agree with this corrigendum; no response could be obtained from KA.

Supporting information

Source Data for Figure 2

Source Data for Figure 3

Source Data for Figure 4