Since the identification of essential protein-translocation components
in the endoplasmic reticulum membrane, research efforts have concentr
ated on the elucidation of the molecular mechanism of protein transpor
t across this membrane. Recent results have provided new information a
s to how proteins are targeted to, and inserted into, the translocatio
n site during translation. Post-translational translocation has also b
een examined and is distinct from cotranslational translocation with r
espect to the mechanism and membrane protein components involved.