Final answer:
The role that is not a function of integrins is allowing diffusion to occur through the plasma membrane. Integrins are involved in cell adhesion and communication between the intracellular and extracellular environments, but not in diffusion processes.
Step-by-step explanation:
Functions of Integrins
The function that is NOT a role of integrins is C. allow diffusion to occur through the plasma membrane. Integrins are integral membrane proteins that play a critical role in attaching a cell to the extracellular matrix (ECM) and in cell-to-cell adhesion. They function as adhesion molecules, connecting the cell's internal cytoskeleton to the ECM, thus providing structural support and helping to establish cell polarity. Moreover, integrins play a significant role in signal transduction by mediating communication between the intracellular and extracellular environments, which is crucial in processes such as cell migration, growth, and differentiation.
Desmosomes, another type of intercellular junction, serve to glue components of the matrix together providing the tissue with mechanical strength. However, integrins themselves are not involved in allowing diffusion through the plasma membrane; that function is associated with other structures like gap junctions in animal cells and plasmodesmata in plant cells, which facilitate chemical communication and molecular movement between cells.