In cooperation with other chaperones, Hsp70s are key components that facilitate folding of de novo synthesized proteins, assist translocation of precursor proteins into organelles, and are responsible for degradation of damaged protein under stress conditions (Probable). ATP-dependent molecular chaperone that assists folding of unfolded or misfolded proteins under stress conditions. Mediates plastid precursor degradation to prevent cytosolic precursor accumulation, together with the E3 ubiquitin-protein ligase CHIP. Recognizes specific sequence motifs in transit peptides and thereby led to precursor degradation through the ubiquitin-proteasome system. Plays a critical role in embryogenesis. In cooperation with other chaperones, Hsp70s are key components that facilitate folding of de novo synthesized proteins, assist translocation of precursor proteins into organelles, and are responsible for degradation of damaged protein under stress conditions. Interacts with CHIP (PubMed:20028838). Interacts with HSFA1A/HSF1 (PubMed:11807141). Expressed in cotyledons, leaves, stems, vascular bundles, roots, stigmas and anthers. Up-regulated during seed maturation. Induced by heat shock and cold (PubMed:11402207). Induced by high light treatment and oxidative stress (PubMed:19704521). Up-regulated by viral infection (PubMed:15805473). Induced by infection with the bacterial pathogen Pseudomonas syringae (PubMed:18065690). Induced by abscisic acid (ABA), salt stress, osmotic shock, brassinosteroid, cytokinin and auxin (PubMed:28004282). Abnormal embryogenesis. Defective seedlings with high levels of reactive oxygen species and monoubiquitinated LHCB4 precursors (PubMed:20028838). No visible phenotype under normal growth conditions (PubMed:28004282). Belongs to the heat shock protein 70 (TC 1.A.33) family. DnaK subfamily.