cytoskeleton Flashcards
what is cytoskeleton
network of protein polymers in the cell which provide mechanical support for the ecll
cytoskeletal protiens
actin
intermmediate filaments
microtubels
function of the cytoskeleton
acts as muscle/skeleton for the cell cell migration organelle movement mechanical support shape/organisation of the cell
where are actin filaments found
everywhrer
concentrated under the membrane
size of the protein polymerns
actin smallest
microtubule biggest
actin
can form microvilli/lamelipodia
carry out cellular moments, phagocytosis, cytokinesis, muscle contraction
what is actin constituents
G actin
F actin
what occurs during phagoytosis
rearrangement of the acid cytoskeleton
stages of actin polymerisation
nucleation - formation of actin nucleus
elongation - monomers added at the positive end
steady state
what is phalloidin
toxin which targets cytoskeletal protiens
what does phalloidi do
blocks F actin
therefore stops actin and depolymerisation
what is and does cytochalasin do
fungal protein
stops actin polymerisation
cells unable to take things up
what are intermediate filaments
nuclear and cytoplasmic meshworks
maintain shape
types of intermediate filaments
keratins
lamina
desmin
keratin
heteropolymer (type I and II protiens)
pairing of protein is specific
pairing predictive of: differentiation status and epithelial proliferation
where does a keratin mutation occur
K14 or K5
cells separate
what is immunohistochemistry
antibody based staining technique
microtubules
strong hollow tubes
heterodimer
polarised and dynamic
structural suppot
molecular motors
microtubules used as anchor
transport vessels e.g. vesicles move along the microtubles
microtubules in cell division
mitotic spindle = microtubule and microtubule dependant motor proteins
attatch to chromosomes at kinetochores
dyenein moves kinetochore poleward along
what can microtubles bundles form
cilia and flagella
how do actin and microtubules work together
microtubules direct actin assembly
cell juncitions
tight junction desmosomes hemidesomosomes adherans junctions gap junctions
functions of cell junctions
tight junction - cell adherence, water tight seal
adherans junction - connects actin filament bundle with adjacent cells
gap junctions - allows flow of ions and water between cells
desmosomes - connects intermmediate filaments between adjecent cells
hemidesomosomes - connect intermediate filaments to ECM
what are microtubule interacting drugs and fucntion
taxol
binds and stablises microtubles (chromosomes don’t move)
cells die by apoptosis
colchicine
prevents cell migration
