Intermediate filaments help protect animal cells from mechanical stress because ____________

Question

(a) filaments directly extend from the interior of the cell to the extracellular space and into the next cell, linking one cell to the next, helping to distribute locally applied forces.
(b) filaments in each cell are indirectly connected to the filaments of a neighboring cell through the desmosome, creating a continuous mechanical link between cells.
(c) filaments remain independent of other cytoskeletal elements and keep the mechanical stress away from other cellular components.
(d) filaments make up the desmosome junctions that connect cells; these junctions are more important than the internal network of filaments for protecting cells against mechanical stress.

Answer 1

Choice (b) is correct. Intermediate filaments do not directly extend from cell to cell [choice (a)]. The linking of intermediate filaments to other cytoskeletal elements (like actin) is thought to help protect cells from mechanical stress [choice (c)]. Desmosome junctions are made up of many different kinds of proteins including cadherins in the extracellular space (which mediate cell–cell adhesion) as well as proteins within the cytoplasm that mediate the attachment of desomosomes to intermediate filaments. These junctions alone are not sufficient for protection against mechanical stress and need the interaction with the intermediate filament network in the cell [choice (d)].