In cell biology, a bleb is an irregular bulge in the plasma membrane of a cell caused by localized decoupling of the cytoskeleton from the plasma membrane (recently reviewed in [1]). Blebbing is the term used to describe the formation of blebs.
The process of apoptosis, with blebbing shown in the middle illustration
Physiological Functions
During apoptosis (programmed cell death), the cell's cytoskeleton breaks up and causes the membrane to bulge outward (reviewed in [2]). These bulges may separate from the cell, taking a portion of cytoplasm with them, to become known as apoptotic bodies. Phagocytic cells eventually consume these fragments and the components are recycled (see figure).
Blebbing also has important functions in other cellular processes, including cell locomotion, cell division, and physical or chemical stresses. The types of blebs vary greatly, including variations in bleb growth rates, size, contents, and actin content.
Pharmacology
A chemical known as blebbistatin (Sigma Aldrich) was recently shown to inhibit the formation of blebs. This agent was discovered in a screen for small molecule inhibitors of nonmuscle myosin IIA and was shown to lower the affinity of myosin with actin [3][4], thus altering the contractile forces that impinge on the cytoskeleton-membrane interface.
Notes
- ^ Fackler and Grosse, 2008
- ^ Vermeulen et al., 2005
- ^ Kovács et al., 2004
- ^ Limouze et al., 2004
References
- (−)-Blebbistatin - Sigma-Aldrich
- Charras GT, Coughlin M, Mitchison TJ, Mahadevan L. (2008). Life and times of a cellular bleb. Biophys J., 94(5):1836-53.
- Charras GT, Hu CK, Coughlin M, Mitchison TJ. (1996). Reassembly of the contractile actin cortex in cell blebs. J Cell Biol. 175(3):477-90.
- Dai J, Sheetz MP. (1999) Membrane tether formation from blebbing cells. Biophys J. 77(6):3363-70.
- Drug Stops Motor Protein, Shines Light on Cell Division - FOCUS March 21, 2003. Retrieved April 8, 2008.
- Fackler OT, Grosse R. (2008). Cell motility through plasma membrane blebbing. J Cell Biol. 181(6):879-84.
- Hagmann J, Burger MM, Dagan D. (1999). Regulation of plasma membrane blebbing by the cytoskeleton. J Cell Biochem. 73(4):488-99.
- Kovács M et al. (2004). Mechanism of Blebbistatin Inhibition of Myosin II, J Biol Chem., 279(34):35557-35563.
- Limouze J, Straight AF, Mitchison T, Sellers JR. (2004). Specificity of blebbistatin, an inhibitor of myosin II. J Muscle Res Cell Motil. 25(4-5):337-41.
- Vermeulen K, Van Bockstaele DR, Berneman ZN. (2005) Apoptosis: mechanisms and relevance in cancer. Ann Hematol. 84(10):627-39.
|
