Functions as a co-chaperone, regulating the substrate binding and activating the ATPase activity of chaperones of the HSP70/heat shock protein 70 family (, ). In parallel, also contributes to the ubiquitin-dependent proteasomal degradation of misfolded proteins (, ). Thereby, may regulate the aggregation and promote the functional recovery of misfolded proteins like HTT, MC4R, PRKN, RHO and SOD1 and be crucial for many biological processes (  ). Isoform 1 which is localized to the endoplasmic reticulum membranes may specifically function in ER-associated protein degradation of misfolded proteins .
Subcellular locations: Cytoplasm, Nucleus
Subcellular locations: Endoplasmic reticulum membrane
More abundantly expressed in neocortex, cerebellum, spinal cord and retina where it is expressed by neuronal cells (at protein level) (, ). Detected at much lower level in non-neuronal tissues including kidney, lung, heart, skeletal muscle, spleen and testis (at protein level) (, ). Isoform 1 is more abundant in neocortex and cerebellum compared to isoform 2 (at protein level) .