Enables Hsp70 protein binding activity; chaperone binding activity; and transmembrane transporter binding activity. Involved in positive regulation of delayed rectifier potassium channel activity; positive regulation of gene expression; and positive regulation of voltage-gated potassium channel activity involved in ventricular cardiac muscle cell action potential repolarization. Located in perinuclear region of cytoplasm. [provided by Alliance of Genome Resources, Apr 2022]