The molecular basis of coupling of translocation and N-glycosylation.

Protein translocation and N-glycosylation are essential coordinated cellular processes that are mediated by the translocon and the oligosaccharyl transferase (OT), respectively. The recent identification of several specific interactions between the OT subunits and the translocon provides a molecular basis for the coupling of these two processes. Data suggest that multiple OT isoforms with different affinities for the translocon and ribosome and with heterogeneous subunit composition might exist in the endoplasmic reticulum (ER) membrane, thereby providing a means of regulating protein N-glycosylation.