ATPase involved in protein folding and NLS-directed nuclear transport; HSP70 family member; required for ubiquitin-dependent degradation of short-lived proteins; forms a chaperone complex with Ydj1p; localizes to the nucleus, cytoplasm and cell wall; unique functional specificity in the propagation of yeast [URE3] prions and vacuolar-mediated degradation of gluconeogenic enzymes; general targeting factor of Hsp104p to prion fibrils; 98% identity with paralog Ssa2p