Both types of ribophorins develop a key role in the binding of ribosomes to the rough endoplasmic reticulum as well as in the co-translational processes that depend on this interaction. The content of ribophorin of the rough endoplasmic reticulum is equal to the stoichiometric number of ribosomal units. Therefore, this suggests the great importance, abundance and good preservation of these proteins in the reticulum. Consequently, defects in the genes that encode these proteins may cause congenital disorders and devastating consequences; ribophorin I and II are encoded by the genes RPN1 and RPN2 respectively.