The protein that is translated from this mRNA still has a signal sequence that targets it to the ER, but no hydrophobic region that traps it in the membrane. When it transits to the surface in the vesicle, it is released when the vesicle fuses with the cell membrane. You know now that vesicles traffic through the cell via the cytoskeletal network. The ER and Golgi, and their vesicles, are, in fact, closely associated with microtubules. I want to take some time to introduce this remarkable structure to you.
Ribosomes have two subunits - small and large.
Eukaryotic cells have a 80S ribosome made up of a 40S small subunit and 60S large subunit. Each of these subunits has a variety of proteins and a rRNA species. Their structure is intricate and they fit together to allow mRNA and emerging protein to tunnel through the structure in an organized manner. Ribosome structure has very recently been clarified by researchers who have advanced our techniques to resolve its structure. Recent data indicates that the ribosome exhibits a hinge type movement during protein synthesis.