Member of the p24 family involved in ER to Golgi transport%3B role in misfolded protein quality control%3B forms heterotrimeric complex with Erp2p%2C Emp24p%2C and Erv25p%3B localized to COPII-coated vesicles%3B ERP1 has a paralog%2C ERP6%2C that arose from the whole genome duplication