Component of the ribosome-associated complex (RAC), a heterodimeric chaperone complex involved in regulation of accurate translation termination and in folding or maintaining nascent polypeptides in a folding-competent state. RAC stimulates the ATPase activity of the ribosome-associated pool of Hsp70-type chaperones SSB1/SSB2 that bind to the nascent polypeptide chain. SSZ1 is required for ZUO1 to function efficiently as a J-protein for SSB1/SSB2. Also involved in pleiotropic drug resistance by post-translational activation of transcription factor PDR1. RAC is a heterodimer of the Hsp70/DnaK-type chaperone SSZ1 and the Hsp40/DnaJ-type chaperone ZUO1. RAC associates with ribosomes via ZUO1. Neither ATP binding nor ATP hydrolysis is required for SSZ1 function. Does not seem to bind unfolded protein substrates, as its C-terminal putative peptide-binding domain is not required for its function. Present with 73600 molecules/cell in log phase SD medium. Belongs to the heat shock protein 70 family.