FRAP has revealed that some proteins move in cell membranes much slower than they move in reconstituted liposomes. Which of the following could account for limited mobility of proteins in cell plasma membranes? a. anchorage to the cell cytoskeleton.

b. association with other proteins in a large complex.

c. anchorage to the extracellular matrix.

d. association with lipid rafts.

e. All could limit protein mobility.

e. All could limit protein mobility

Explanation:

Plasma membrane proteins perform a variety of functions: they act preferentially on transport mechanisms, organizing true tunnels that allow substances to pass into and out of the cell, function as membrane receptors, among other functions. These proteins vary greatly in their mobility, some are as mobile as lipids, while others are practically immobile. But FRAP has revealed that some proteins move in cell membranes much more slowly than in reconstituted liposomes. This limited mobility can be explained by the statement in alternative "E" of the above question.