Enables copper-dependent protein binding activity and tau protein binding activity. Involved in copper ion transport and negative regulation of microtubule polymerization. Located in several cellular components, including axonal growth cone; neuronal cell body; and perinuclear region of cytoplasm. Part of protein-containing complex. Orthologous to human FKBP4 (FKBP prolyl isomerase 4). [provided by Alliance of Genome Resources, Apr 2022]