Question

Intermediate filaments are found mainly in cells that are subject to mechanical stress. Gene mutations that disrupt intermediate filaments cause some rare human genetic diseases. For example, the skin of people with epidermolysis bullosa simplex is very susceptible to mechanical injury; people with this disorder have mutations in their __1__ genes, which code for the intermediate filament found in epithelial cells. These filaments are usually connected from cell to cell through junctions called __2__. The main filaments found in muscle cells belong to the __3__ family; people with disruptions in these intermediate filaments can have muscular dystrophy.

Answer 1

Intermediate filaments made of keratin provide structural support in epithelial cells and connect through desmosomes. Desmin-type intermediate filaments in muscle cells are implicated in muscular dystrophy when disrupted.

Step-by-step explanation:

Intermediate filaments are crucial components of the cellular cytoskeleton, particularly in cells that endure mechanical stress. In epithelial cells, the protein keratin forms these intermediate filaments. Mutations in the keratin genes can lead to conditions like epidermolysis bullosa simplex, where the skin is highly susceptible to mechanical injury due to the lack of structural integrity these intermediate filaments provide.

Cells connect to each other through various types of junctions, and in the case of intermediate filaments, they are commonly linked at desmosomes. These junctions are pivotal for the mechanical stability of tissues. Lastly, in muscle cells, the intermediate filaments are primarily composed of the desmin family, and disruptions in these crucial proteins can result in muscular dystrophies, which affect the muscle's integrity and function.