Enables clathrin adaptor activity and transmembrane transporter binding activity. Involved in endocytosis; membrane fission; and positive regulation of clathrin coat assembly. Located in cytosol; nucleus; and presynapse. Is extrinsic component of cytoplasmic side of plasma membrane; extrinsic component of postsynaptic membrane; and extrinsic component of presynaptic membrane. Is active in Schaffer collateral - CA1 synapse and postsynapse. Biomarker of middle cerebral artery infarction. Orthologous to human EPN1 (epsin 1). [provided by Alliance of Genome Resources, Apr 2022]