Modulation of plasma membrane interaction with the underlying cytoskeleton in cells occurs during numerous cell processes including cell movement and endocytosis. Raucher et al. suggest that the membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2) may be an important regulator of this interaction. By representing overall interactions (cytoskeleton with plasma membrane proteins and/or lipids) with an energy term (membrane tension) that was determined using optical tweezers, the authors show that when membrane PIP2 levels were decreased, membrane tension was reduced. PIP2 levels were reduced in cells by either overexpressing pleckstrin homology domains that sequestered the membrane lipid, by overexpressing a PIP2-specific phosphatase, or by stimulating surface receptors that stimulated the hydrolysis of PIP2. The authors speculate that changes in PIP2 could affect direct interactions between PIP2 and cytoskeletal proteins or could alter actin polymerization.
Raucher, D., Stauffer, T., Chen, W., Shen, K., Guo, S., York, J.D., Sheetz, M.P., and Meyer, T. (2000) Phosphatidylinositol 4,5-bisphosphate functions as a second messenger that regulates cytoskeleton-plasma membrane adhesion. Cell 100: 221-228. [Online Journal]