Enables heat shock protein binding activity; tau protein binding activity; and ubiquitin protein ligase binding activity. Involved in negative regulation of protein ubiquitination and positive regulation of proteasomal protein catabolic process. Located in axon and dendrite. Colocalizes with dendritic microtubule. Orthologous to human BAG2 (BAG cochaperone 2). [provided by Alliance of Genome Resources, Apr 2022]