Previous work from our laboratory has demonstrated that the @entity141 -calmodulin complex inhibits the intrinsic @entity669 kinase activity of the @entity470 ( @entity470 ), and that the receptor can be isolated by @entity141 -dependent calmodulin-affinity chromatography [San Jos  , Bengurija, Geller and Villalobo (1992) J. Biol. Chem. 267, 15237-15245]. Moreover, we have demonstrated that the cytosolic juxtamembrane region of the @entity1 receptor (residues 645-660) binds calmodulin in a @entity141 -dependent manner when this segment forms part of a recombinant fusion protein [Martijn-Nieto and Villalobo (1998) Biochemistry 37, 227-236]. However, demonstration of the direct interaction between calmodulin and the whole receptor has remained elusive. In this work, we show that calmodulin, in the presence of @entity141 , forms part of a high-molecular-mass complex built upon covalent cross-linkage of the @entity1 @entity470 immunoprecipitated from two cell lines overexpressing this receptor. Although several calmodulin-binding proteins co-immunoprecipitated with the @entity470 , suggesting that they interact with the receptor, we demonstrated using overlay techniques that biotinylated calmodulin binds directly to the receptor in a @entity141 -dependent manner without the mediation of any adaptor calmodulin-binding protein. Calmodulin binds to the @entity470 with an apparent dissociation constant (K'(d)) of approx. 0.2-0.3 microM. Treatment of cells with epidermal growth factor, or with inhibitors of protein kinase C and calmodulin-dependent protein kinase II, or treatment of the immunoprecipitated receptor with alkaline phosphatase, does not significantly affect the binding of biotinylated calmodulin to the receptor.

Evidence for the direct interaction between calmodulin and the XXXX @entity470 .

@entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca(2+)'] @entity1 :: ('9606', 'Species') :: ['human'] @entity669 :: ('CHEBI:18186', 'Chemical') :: ['tyrosine'] @entity470 :: ('1956', 'Gene') :: ['EGFR', 'epidermal growth factor receptor']
@entity1 :: (9606,Species) :: ['human']
