Co-chaperone that regulates diverse cellular pathways, such as programmed cell death and stress responses. Binds to the ATPase domain of HSP70/HSC70 chaperones (By similarity). Interacts with HSP70-1. Detected in stems, leaves, flowers and roots. By cold, by salicylic acid (SA), by abscisic acid (ABA) and by pathogen B.cinerea attack. Early flowering and shorter vegetative and reproductive phases, with more branched roots and inflorescences. Early senescence. Enhanced susceptibility to salt stress. Hypersensitivity to light. Truncated N-terminus.