Enables cysteine-type endopeptidase inhibitor activity involved in apoptotic process and mitogen-activated protein kinase kinase binding activity. Involved in several processes, including negative regulation of Notch signaling pathway; positive regulation of cell communication; and regulation of cellular protein metabolic process. Acts upstream of or within phototransduction and regulation of G protein-coupled receptor signaling pathway. Located in cytosol and pseudopodium. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; liver; and respiratory system. Orthologous to human ARRB1 (arrestin beta 1). [provided by Alliance of Genome Resources, Apr 2022]