Final answer:
Integrins serve as anchor proteins that attach cells to the extracellular matrix and relay signals between the cell and its environment. They are not involved in transporting substances between the intracellular and extracellular compartments.
Step-by-step explanation:
Integrins are integral membrane proteins that have multiple functions in cell biology. They are involved in anchor cells to the extracellular matrix (ECM), providing stability and support for cell adhesion. Integrins also relay signals between the cell and the extracellular environment, allowing for communication between cells and their surroundings. However, integrins do not transport substances between the intracellular and extracellular compartments, so option C is not a correct function of integrins.