Final answer:
Claudins play a crucial role in tight junctions by sealing the space between epithelial cells and maintaining selective permeability. Mutation of charged amino acids in claudin to nonpolar ones could weaken the junctions' seal, increasing permeability and potentially leading to disease.
Step-by-step explanation:
The role of claudins in the formation and maintenance of tight junctions is paramount. Claudins are integral membrane proteins that play a crucial role in sealing the space between adjacent epithelial cells, preventing the free passage of substances through the intercellular space. They contribute to the selective permeability of tight junctions and are involved in maintaining the polarity of cells.
When charged amino acids in the large extracellular loop of claudins are mutated to nonpolar amino acids, the tight junctions may be compromised. The charged amino acids are often involved in forming ionic bonds and interactions that are critical for the structural integrity and function of the tight junctions. With the incorporation of nonpolar amino acids, the ability for these loops to interact with adjacent molecules could be reduced, possibly leading to a weaker seal and increased permeability of the junction.
This change has the potential to disrupt the selective barrier function of the epithelial layer, allowing for unwanted substances to pass through the barrier and compromising the distinct internal environment of tissues. Such mutations could have profound implications, possibly resulting in a range of pathological conditions if occurring within the human body.