Some secretory proteins and some integral membrane proteins must pass through a membrane. a ribonucleoprotein known as the signal recognition particle (srp) guides these proteins either to the plasma membrane (in bacteria) or the endoplasmic reticulum (in eukaryotes). put the steps of the membrane translocation of eukaryotic secretory proteins in order, starting after the signal peptide emerges from the ribosome and ending with the protein being transported by vesicles out of the endoplasmic reticiulum.