In contrast , the beta isoform is expressed at very low constitutive levels in both cell types but is only up-regulated in response to mast cell activation signals delivered through the FcepsilonRI or via calcium ionophores .
in contrast , the beta isoform is expressed at very low constitutive levels in both cell types but is only up-regulated in response to mast cell activation signals delivered through the fcepsilonri or via calcium ionophores .
O O O O B-protein_molecule I-protein_molecule O O O O O O O O O O O O O O O O O O B-other_name I-other_name I-other_name I-other_name O O O B-protein_complex O O B-other_organic_compound I-other_organic_compound O