An actin-binding protein that crosslinks actin filaments into contractile bundles.
γ-tubulin ring complex
A protein complex that nucleates the formation of microtubules.
actin
An abundant 43-kd protein that polymerizes to form cytoskeletal filaments.
actin bundle
Actin filaments that are crosslinked into closely packed arrays.
actin network
Actin filaments that are crosslinked into loose three-dimensional meshworks.
actin-binding protein
A protein that binds actin and regulates the assembly, disassembly, and organization of actin filaments.
actin-bundling protein
A protein that crosslinks actin filaments into bundles.
ADF/cofilin
A family of actin-binding proteins that dis-assemble actin filaments.
adherens junction
A region of cell-cell adhesion at which the actin cytoskeleton is anchored to the plasma membrane.
adhesion belt
A beltlike structure around epithelial cells in which a contractile bundle of actin filaments is linked to the plasma membrane.
anaphase A
The movement of daughter chromosomes toward the spindle poles during mitosis.
anaphase B
The separation of the spindle poles during mitosis.
ankyrin
A protein that binds spectrin and links the actin cytoskeleton to the plasma membrane.
Arp2/3 complex
A protein complex that binds actin filaments and initiates the formation of branches.
astral microtubule
A microtubules of the mitotic spindle that extends to the cell periphery.
axonemal dynein
The type of dynein found in cilia and flagella.
axoneme
The fundamental structure of cilia and flagella composed of a central pair of microtubules surrounded by nine microtubule doublets.
basal body
A structure similar to a centriole that initiates the growth of axonemal microtubules and anchors cilia and flagella to the surface of the cell.
brush border
The surface of a cell (e.g., an intestinal epithelial cell) containing a layer of microvilli.
cadherin
A cell adhesion molecule that forms stable cell-cell junctions at adherens junctions and desmosomes.
calmodulin
A calcium-binding protein.
catenin
A group of cytoplasmic proteins (including α-catenin and β-catenin) that link actin filaments to cadherins at adherens junctions.
cell cortex
The actin network underlying the plasma membrane.
centriole
A cylindrical structure consisting of nine triplets of microtubules in the centrosomes of most animal cells.
centrosome
The microtubule-organizing center in animal cells.
chromosomal microtubules
Microtubules of the mitotic spindle that attach to the ends of condensed chromosomes.
cilium
A microtubule-based projection of the plasma membrane that moves a cell through fluid or fluid over a cell.
colcemid
A drug that inhibits the polymerization of microtubules.
colchicine
A drug that inhibits the polymerization of microtubules.
contractile bundle
A bundle of actin filaments that interacts with myosin II and is capable of contraction.
contractile ring
A structure of actin and myosin II that forms beneath the plasma membrane during mitosis and mediates cytokinesis.
cytochalasin
A drug that blocks the elongation of actin filaments.
cytokinesis
Division of a cell following mitosis or meiosis.
cytoplasmic dynein
The form of dynein associated with microtubules in the cytoplasm.
desmin
An intermediate filament protein expressed in muscle cells.
desmosome
A region of contact between epithelial cells at which keratin filaments are anchored to the plasma membrane. See also hemidesmosome.
dynactin
A protein that acts with cytoplasmic dynein to move cargo along microtubules.
dynamic instability
The alternation of microtubules between cycles of growth and shrinkage.
dynein
A motor protein that moves along microtubules towards the minus end.
dystrophin
A cytoskeletal protein of muscle cells.
ERM proteins
A family of proteins that link actin filaments to the plasma membranes of many kinds of cells.
filamentous [F] actin
Actin monomers polymerized into filaments.
filamin
An actin-binding protein that crosslinks actin filaments into networks.
filopodium
A thin projection of the plasma membrane supported by actin bundles.
fimbrin
An actin-bundling protein involved in formation of cell surface projections.
flagellum
A microtubule-based projection of the plasma membrane that is responsible for cell movement.
focal adhesion
A site of attachment of cells to the extracellular matrix at which integrins are linked to bundles of actin filaments.
fodrin
Nonerythroid spectrin.
formin
An actin-binding protein that nucleates and polymerizes actin filaments.
globular [G] actin
Monomers of actin that have not been assembled into filaments.
hemidesmosome
A region of contact between cells and the extracellular matrix at which keratin filaments are attached to integrin.
integrin
A transmembrane protein that mediates the adhesion of cells to the extracellular matrix.
intermediate filament
A cytoskeletal filament about 10 nm in diameter that provides mechanical strength to cells in tissues. See also keratins and neurofilaments.
keratin
A type of intermediate filament protein of epithelial cells.
kinesin
A motor protein that moves along microtubules toward the plus end.
kinetochore microtubule
A microtubule of the mitotic spindle that attaches to condensed chromosomes at their centromeres.
lamellipodium
A broad, actin-based extension of the plasma membrane involved in the movement of fibroblasts.
microfilament
A cytoskeleton filament composed of actin.
microspike
See filopodium.
microtubule
A cytoskeletal component formed by the polymerization of tubulin into rigid, hollow rods about 25 nm in diameter.
microtubule-associated protein (MAP)
A protein that binds to microtubules and modifies their stability.
microvillus
An actin-based protrusion of the plasma membrane, abundant on the surfaces of cells involved in absorption.
mitotic spindle
An array of microtubules extending from the spindle poles that is responsible for separating daughter chromosomes during mitosis. See also kinetochore microtubules, polar microtubules, chromosomal microtubules, and astral microtubules.
molecular motor
A protein that generates force and movement by converting chemical energy to mechanical energy.
muscle fiber
A large cell of skeletal muscle, formed by the fusion of many individual cells during development.
myofibril
A bundle of actin and myosin filaments in muscle cells.
myosin
A protein that interacts with actin as a molecular motor.
myosin I
A type of myosin that acts to transport cargo along actin filaments.
myosin II
The type of myosin that produces contraction by sliding actin filaments.
myosin light-chain kinase
A protein kinase that activates myosin II by phosphorylating its regulatory light chain.
nebulin
A protein that regulates the length of actin filaments in muscle cells.
neurofilament (NF) protein
A member of a family of major intermediate filament proteins of many types of mature nerve cells.
nexin
A protein that links microtubule doublets to each other in the axoneme.
pericentriolar material
The material in the centrosome that initiates microtubule assembly.
phalloidin
A drug that binds to actin filaments and prevents their disassembly.
plakin
A member of a family of proteins that link intermediate filaments to other cellular structures.
polar microtubule
One of a class of microtubules of the mitotic spindle that overlap in the center of the cell and push the spindle poles apart.
profilin
An actin-binding protein that stimulates the assembly of actin monomers into filaments.
pseudopodium
An actin-based extension of the plasma membrane responsible for phagocytosis and amoeboid movement.
sarcomere
The contractile unit of muscle cells composed of interacting myosin and actin filaments.
sarcoplasmic reticulum
A specialized network of membranes in muscle cells that stores a high concentration of Ca2+.
sliding filament model
The model of muscle contraction in which contraction results from the sliding of actin and myosin filaments relative to each other.
spectrin
A major actin-binding protein of the cell cortex.
stereocilium
A specialized microvillus of auditory hair cells.
stress fiber
A bundle of actin filaments anchored at sites of cell adhesion to the extracellular matrix.
talin
A protein that mediates the association of actin filaments with integrins at focal adhesions.
taxol
A drug that binds to and stabilizes microtubules.
titin
A large protein that acts as a spring to keep myosin filaments centered in the muscle sarcomere.
treadmilling
A dynamic behavior of actin filaments and microtubules in which the loss of subunits from one end of the filament is balanced by their addition to the other end.
tropomyosin
A fibrous protein that binds actin filaments and regulates contraction by blocking the interaction of actin and myosin.
troponin
A complex of proteins that binds to actin filaments and regulates skeletal muscle contraction.
tubulin
A cytoskeletal protein that polymerizes to form microtubules.
twinfilin
An actin-binding protein that stimulates the assembly of actin monomers into filaments.
video-enhanced microscopy
The combined use of video cameras with the light microscope to allow the visualization of small objects.
villin
The major actin-bundling protein of intestinal microvilli.
vimentin
An intermediate filament protein found in a variety of different kinds of cells.
vinblastine
A drug that inhibits microtubule polymerization.
vincristine
A drug that inhibits microtubule polymerization.
vinculin
A protein that mediates the association of actin filaments with integrins at focal adhesions.
WASP/Scar complex
A protein complex that stimulates actin filament branching.
