Enables K63-linked polyubiquitin modification-dependent protein binding activity; identical protein binding activity; and ionotropic glutamate receptor binding activity. Involved in several processes, including brown fat cell proliferation; energy homeostasis; and positive regulation of long-term synaptic potentiation. Acts upstream of or within negative regulation of transcription by RNA polymerase II. Located in several cellular components, including aggresome; autolysosome; and sperm midpiece. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; limb; and sensory organ. Used to study Paget's disease of bone. Human ortholog(s) of this gene implicated in GNE myopathy; Paget's disease of bone; and frontotemporal dementia and/or amyotrophic lateral sclerosis-3. Orthologous to human SQSTM1 (sequestosome 1).