regulates protein folding in endoplasmic reticulum regulation of protein folding in endoplasmic reticulum Any process that modulates the rate, frequency or extent of the protein folding process that takes place in the endoplasmic reticulum (ER). Secreted, plasma membrane and organelle proteins are folded in the ER, assisted by chaperones and foldases (protein disulphide isomerases), and additional factors required for optimal folding (ATP, Ca2+ and an oxidizing environment to allow disulfide bond formation). biological_process dph 2009-08-14T01:12:00Z GO:0060904 biological regulation regulation of protein folding