Final answer:
Tight junctions restrict membrane proteins to specific domains of the cell in the epithelium by forming watertight seals between adjacent cells. These junctions prevent materials from leaking between cells and compartmentalize the cell membrane.
Step-by-step explanation:
Tight junctions are responsible for restricting membrane proteins to specific domains of the cell in the epithelium. Tight junctions are watertight seals between two adjacent animal cells and are typically found in epithelial tissues that line internal organs and cavities, such as the urinary bladder. These junctions prevent materials from leaking between the cells and effectively compartmentalize the cell membrane into subregions.