The ErbB-family receptors, consisting of the epidermal growth factor receptor (EGFR/ErbB1/HER1), ErbB2/HER2, ErbB3/HER3, and ErbB4/HER4, play pivotal roles in cell proliferation, migration, and survival of the epithelial cells. However, due to their functional redundancy, it remains unknown to which extent each of the four ErbB proteins contributes to these biological outputs. We here knocked out each, combination, or all of the four ErbB genes in Madin-Darby canine kidney (MDCK) cells to delineate the contribution of each ErbB gene. During collective cell migration of MDCK cells, activation of extracellular signal-regulated kinase (ERK) is propagated from the leader cells to the follower cells. These ERK activation waves were mediated primarily by ErbB1 and auxiliary by the ErbB2/ErbB3 heterodimer. Either ErbB1 or the ErbB2/ErbB3 complex was sufficient for the G1/S progression of MDCK cells. The saturation cell density was markedly reduced in cells deficient from all ErbB proteins due to apoptosis. ErbB1 or ErbB2 alone is sufficient to prevent apoptosis at high cell density. Because ErbB2 does not bind to any ErbB ligands, these observations indicate that the ligand-independent ErbB2 activity is sufficient for preventing apoptosis at high cell density, but not for cell proliferation. Thus, systematic knockout of ErbB-family genes delineated the roles of each ErbB receptor in collective cell migration, cell proliferation, and survival at high cell density.
Most of the time-lapse images were obtained with epifluorescence microscopy. Some of the experiments were done with confocal microscopy.
Kimiya Matsuda, Daiki Hirayama, Naoya Hino, Sota Kuno, Asako Sakaue-Sawano, Atsushi Miyawaki, Michiyuki Matsuda, Kenta Terai (2023) Knockout of all ErbB-family genes delineates their roles in proliferation, survival, and migration., Journal of cell science
Published in 2023 Jul 31 (Electronic publication in July 31, 2023, midnight )
(Abstract) The ErbB-family receptors play pivotal roles in the proliferation, migration, and survival of epithelial cells. Because our knowledge on the ErbB-family receptors was obtained largely by the exogenous application of their ligands, it remains unknown to which extent each of the ErbB contributes to these outputs. We here knocked out each ErbB gene, various combinations of ErbB genes, or all in Madin-Darby canine kidney cells to delineate the contribution of each gene. ERK activation waves during collective cell migration were mediated primarily by ErbB1 and secondarily by the ErbB2/ErbB3 heterodimer. Either ErbB1 or the ErbB2/ErbB3 complex was sufficient for the G1/S progression. The saturation cell density was markedly reduced in cells deficient in all ErbB-proteins, but not cells retaining only ErbB2, which cannot bind to ligands. Thus, the ligand-independent ErbB2 activity is sufficient for preventing apoptosis at high cell density. In short, systematic knockout of ErbB-family genes delineated the roles of each ErbB receptor.