Enables SH3 domain binding activity; kinase binding activity; and small GTPase binding activity. Involved in several processes, including cellular response to growth factor stimulus; cellular response to hormone stimulus; and negative regulation of macromolecule metabolic process. Located in cytosol and plasma membrane. Orthologous to human ERRFI1 (ERBB receptor feedback inhibitor 1). [provided by Alliance of Genome Resources, Apr 2022]