Final answer:
The basic building block of intermediate filament assembly is a dimer, which further aggregates to form tetramers and larger filament bundles, providing structure and tensile strength to cells.
Step-by-step explanation:
The basic building block of intermediate filament assembly is a dimer, which consists of a pair of monomers. Each monomer has globular domains at their C- and N-terminal ends, separated by coiled rod regions that provide elasticity, comparable to titin molecules. These dimers aggregate to form tetramers, and subsequently, larger filament bundles that confer tensile strength and resistance to mechanical stress on cells.
Intermediate filaments play a critical role in maintaining cell shape and structure, resisting tension, supporting cell-cell junctions such as desmosomes, and anchoring cells to extracellular structures.