BiP and Sec63p are required for both co- and posttranslational protein translocation into the yeast endoplasmic reticulum.
Brodsky JL, Goeckeler J, Schekman R.
Proc Natl Acad Sci U S A. 1995 Oct 10;92(21):9643-6. doi: 10.1073/pnas.92.21.9643.PMID: 7568189