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.