The process by which protein synthesis is closely coupled with the translocation of the growing protein to the destination within the cell, such as rough endoplasmic reticulum (rER) and plasma membranes
In eukaryotes, the secretory proteins and membrane proteins are translocated to the rER and plasma membrane, respectively by means of cotranslational transport pathway.
This pathway also occurs in prokaryotes when the nascent protein is moved from the cytosol to the plasma membrane where it will continue growing to become a membrane protein.
(For in-depth information, see reference 1.)
In: Jékely G. Eukaryotic membranes and cytoskeleton: origins and evolution. Texas: Springer. p52-60.