Endogenous calmodulin interacts with the epidermal growth factor receptor in living cells

• Published in: FEBS letters Vol. 559; no. 1; pp. 175 - 180
• Main Authors: Li, Hongbing, Ruano, Marı́a José, Villalobo, Antonio
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 13.02.2004
• Subjects: [Ca2+]cyt, cytosolic concentration of free calcium ion; Binding Sites - genetics; Calmodulin; Calmodulin - antagonists & inhibitors; Calmodulin - metabolism; CaM, calmodulin; CaMK-II, calmodulin-dependent protein kinase II; Cell Line, Tumor; Dose-Response Relationship, Drug; EGF, epidermal growth factor; EGFR, EGF receptor; EGTA, [ethylene bis(oxyethylenenitrilo)]-tetraacetic acid; Epidermal growth factor receptor; FBS, fetal bovine serum; Humans; IgG, immunoglobulin G; Kinetics; Living cell; Mutation; Phosphorylation; PMSF, phenylmethylsulfonyl fluoride; Precipitin Tests; Protein Binding; PVDF, polyvinylidene difluoride; Receptor, Epidermal Growth Factor - genetics; Receptor, Epidermal Growth Factor - metabolism; SDS–PAGE, polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate; Sulfonamides - pharmacology; Transfection; W12, N-(4-aminobutyl)-1-naphthalenesulfonamide; W13, N-(4-aminobutyl)-5-chloro-1-naphthalenesulfonamide; W7, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide; EGFR, EGF receptor; W13, N-(4-aminobutyl)-5-chloro-1-naphthalenesulfonamide; EGF, epidermal growth factor; FBS, fetal bovine serum; SDS–PAGE, polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate; CaM, calmodulin; Epidermal growth factor receptor; [Ca 2+] cyt, cytosolic concentration of free calcium ion; EGTA, [ethylene bis(oxyethylenenitrilo)]-tetraacetic acid; IgG, immunoglobulin G; PMSF, phenylmethylsulfonyl fluoride; Living cell; PVDF, polyvinylidene difluoride; CaMK-II, calmodulin-dependent protein kinase II; W7, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide; Calmodulin; W12, N-(4-aminobutyl)-1-naphthalenesulfonamide
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(04)00067-5

We have previously shown that exogenous calmodulin (CaM) binds to the epidermal growth factor receptor (EGFR) at its cytosolic juxtamembrane region inhibiting its tyrosine kinase activity. We demonstrate in this report that endogenous CaM binds to EGFR in intact cells as CaM co-immunoprecipitates with EGF-activated and non-activated receptors. We also show in living cells that cell-permeable CaM inhibitors prevent the full transphosphorylation of wild type EGFR but not the transphosphorylation of an insertional EGFR mutant in which the CaM-binding domain was divided into two parts. Overall these results suggest that CaM interacts with EGFR in vivo.