Before revision:  The goal of this review is to synthesize the numerous and disparate observations on the membrane trafficking of the five major junction transmembrane proteins accumulated to date to comprehend the current state of the art, to highlight differences and similarities among the trafficking pathways, and to identify topics that are not fully understood.
After revision:  The goal of this review is to synthesize studies published mostly in the last 25 years on the membrane trafficking of the five major junction transmembrane proteins accumulated to date to comprehend the current state of the art, to highlight differences and similarities among the trafficking pathways, and to identify topics that are not fully understood.