In the membrane-skeleton fence model, what restricts the mobility of membrane proteins?

The correct answer identifies the cytoskeleton as a crucial component in restricting the mobility of membrane proteins within the membrane-skeleton fence model. In this model, the cytoskeleton provides a structural framework beneath the plasma membrane, anchoring certain proteins in specific areas and creating compartments within the membrane. This physical network of filamentous protein structures, including actin filaments and microtubules, limits the lateral mobility of membrane proteins by establishing distinct zones or barriers.

As a result, while membrane proteins are indeed capable of lateral movement within the lipid bilayer, the presence of the cytoskeleton influences their distribution and mobility, allowing for more organized functions and interactions within the cell membrane. This organization is vital for cellular processes such as signaling, adhesion, and maintaining the integrity of the cell structure.

Other options, while related to membrane dynamics, do not specifically address the significant role of the cytoskeleton in organizing and restricting membrane protein movement.