jats:titleAbstract</jats:title>jats:pMaintenance of protein homeostasis depends on cellular stress response pathways that mediate adaptive changes in gene expression. In the endoplasmic reticulum additional mechanisms adjust the availability of the abundant Hsp70-type chaperone, BiP, during short-term fluctuations in the unfolded protein load. Here, recent insights into the regulation of BiP by incorporation into inactive oligomers and reversible AMPylation are discussed.</jats:p>