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Bleb (cell biology)
Encyclopedia
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. Blebbing is the term used to describe the formation of blebs and is sometimes referred to as zeiosis.
(programmed cell death), the cell's cytoskeleton breaks up and causes the membrane to bulge outward. 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.
and was shown to lower the affinity of myosin
with actin
, thus altering the contractile forces that impinge on the cytoskeleton-membrane interface.
Cell biology
Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...
, a bleb is an irregular bulge in the plasma membrane of a cell caused by localized decoupling of the cytoskeleton
Cytoskeleton
The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...
from the plasma membrane. Blebbing is the term used to describe the formation of blebs and is sometimes referred to as zeiosis.
Physiological functions
During apoptosisApoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
(programmed cell death), the cell's cytoskeleton breaks up and causes the membrane to bulge outward. These bulges may separate from the cell, taking a portion of cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the 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
Actin
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...
content.
Pharmacology
A chemical known as blebbistatin was recently shown to inhibit the formation of blebs. This agent was discovered in a screen for small molecule inhibitors of nonmuscle myosin IIAMYH9
Myosin, heavy chain 9, non-muscle is a protein which in humans is encoded by the MYH9 gene.-Clinical significance:MYH9 polymorphisms have been shown to associate with glomerulosclerosis and non-diabetic end stage renal disease in African Americans and in Hispanic Americans, though it was later...
and was shown to lower the affinity of myosin
Myosin
Myosins comprise a family of ATP-dependent motor proteins and are best known for their role in muscle contraction and their involvement in a wide range of other eukaryotic motility processes. They are responsible for actin-based motility. The term was originally used to describe a group of similar...
with actin
Actin
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...
, thus altering the contractile forces that impinge on the cytoskeleton-membrane interface.