Soluble factors stimulating secretory protein translocation in bacteria and yeast can substitute for each other

Abstract

mRNA for prepro-α-factor (ppα), a yeast secretory glycoprotein, was translated in a wheat germ cell-free system that was posttranslationally supplemented either with inverted vesicles from the plasma membrane of Escherichia coli (INV) or with microsomes from Saccharomyces cerevisiae. A postribosomal supernatant (PRS) from E. coli was found to stimulate translocation of ppα across the INV membrane. A yeast PRS could substitute for its E. coli counterpart. Likewise, an E. coli PRS could substitute for a yeast PRS and stimulate translocation of ppα across yeast microsomal membranes.