Enables IgE binding activity and IgE receptor activity. Acts upstream of or within several processes, including leukotriene biosynthetic process; positive regulation of immune response; and positive regulation of macromolecule metabolic process. Located in external side of plasma membrane. Is integral component of plasma membrane. Orthologous to human FCER1A (Fc fragment of IgE receptor Ia). [provided by Alliance of Genome Resources, Apr 2022]