Final answer:
Actin is NOT an integral membrane protein; it is part of the cytoskeleton, whereas the other options listed are associated with transport and communication functions within the cellular membrane.
Step-by-step explanation:
The correct answer to the question, which element is NOT an integral membrane protein, is E) actin. Integral membrane proteins are tightly attached to the cellular membrane and play various roles in transport and cell communication. Examples of integral membrane proteins include carrier proteins for mediated transport (A), connexons (B), which form gap junctions, ion channel proteins (C) that facilitate ion diffusion, and occludins (D) that are part of tight junctions. Actin (E), however, is not an integral membrane protein but rather part of the cytoskeleton, responsible for cell structure and movement.