The heat shock protein 70 (Hsp70) family contains both heat-inducible and constitutively expressed members. The latter are called heat-shock cognate (Hsc) proteins. The heat shock 70 kDa protein 8 also known as Hsc70 belongs to the heat-shock cognate subgroup. This protein binds to nascent polypeptides to facilitate correct protein folding. In order to properly fold non-native proteins, Hsp70 chaperones interact with the hydrophobic peptide segments of proteins in an ATP-controlled fashion. Though the exact mechanism still remains unclear, there are at least two alternative modes of action: kinetic partitioning and local unfolding. In kinetic partitioning, Hsp70s repetitively bind and release substrates in cycles that maintain low concentrations of free substrate. This effectively prevents aggregation while allowing free molecules to fold to the native state. In local unfolding, the binding and release cycles induce localized unfolding in the substrate, which helps to overcome kinetic barriers for folding to the native state. Ultimately, its role in protein folding contributes to its function in signal transduction, apoptosis, protein homeostasis, and cell growth and differentiation. Hsc70 is known to localize to the cytoplasm and lysosome, where it participates in chaperone-mediated autophagy by aiding the unfolding and translocation of substrate proteins across the membrane into the lysosomal lumen. Through this pathway, Hsc70 also contributes to the degradation of the proapoptotic BBC3/PUMA under normal conditions, thus conferring cytoprotection.