2025-06-112025-06-112021-07Abdelli, F., Jellali, K., Anguita, E., González-Muñoz, M., Villalobo Polo, E., Madroñal, I.,...,Villalobo, A. (2021). The role of the calmodulin-binding and calmodulin-like domains of the epidermal growth factor receptor in tyrosine kinase activation. Journal of Cellular Physiology, 236 (7), 4997-5011. https://doi.org/10.1002/jcp.30205.0021-95411097-4652https://hdl.handle.net/11441/174235The epidermal growth factor receptor (EGFR) harbors a calmodulin (CaM)-binding domain (CaM-BD) and a CaM-like domain (CaM-LD) upstream and downstream, respectively, of the tyrosine kinase (TK) domain. We demonstrate in this paper that deletion of the positively charged CaM-BD (EGFR/CaM-BD∆) inactivated the TK activity of the receptor. Moreover, deletion of the negatively charged CaM-LD (EGFR/CaM-LD∆), leaving a single negative residue (glutamate), reduced the activity of the receptor. In contrast, substituting the CaM-LD with a histidine/valine-rich peptide (EGFR/InvCaM-LD) caused full inactivation. We also demonstrated using confocal microscopy and flow cytometry that the chimera EGFR-green fluorescent protein (GFP)/CaM-BD∆, the EGFR/CaM-LD∆, and EGFR/InvCaM-LD mutants all bind tetramethylrhodamine-labelled EGF. These EGFR mutants were localized at the plasma membrane as the wild-type receptor does. However, only the EGFR/CaM-LD∆ and EGFR/InvCaM-LD mutants appear to undergo ligand-dependent internalization, while the EGFR-GFP/CaM-BD∆ mutant seems to be deficient in this regard. The obtained results and in silico modelling studies of the asymmetric structure of the EGFR kinase dimer support a role of a CaM-BD/CaM-LD electrostatic interaction in the allosteric activation of the EGFR TK.application/pdf31 p.engCalmodulinCalmodulin-binding domainCalmodulin-like domainEpidermal growth factor receptorReceptor internalizationTyrosine kinase activityinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess10.1002/jcp.30205