epidermolysis bullosa
fragile skin caused by keratin mutations
provides shape and organization to the cell
cytoskeleton
involved in cell division, chromosome separation
microtubules
give mechanical strength, help cells withstand stretching, form network
intermediate filaments
where intermediate filaments anchor
desmosomes
structure that intermediate filaments form
ropelike, rod-like alpha helix with unstructured ends
structure that intermediate filaments can also form with the help of certain proteins called lamin
nuclear lamina
Progeria
mutation in lamin A, causes early aging symptoms
what intermediate filaments are stabilized by
other proteins
plectin
bundles of intermediate filaments
KASH and SUN
connect intermediate filaments in nucleus with intermediate filaments in the cytoskeleton
nickname for microtubules
"master organizers"
where microtubules grow out of, act as organizing centers
centrosomes
what microtubules are made of
tubulin alpha (-) and beta (+) subunits
serves as a starting place for microtubule formation
y-tubulin
makeup of the centrosome
pair of centrioles + the protein matrix
what side growth in microtubules occurs on (generally)
the positive end
what is meant by dynamic instability
microtubules switch between polymerization and depolymerization
what drives microtubule dynamics
GTP hydrolysis
GDP bound dimers
don't bind as tightly, more prone to fall apart
GTP bound dimers
bind more tightly, encourage growth
help stabilize microtubules against depolarization
accessory proteins
use ATP hydrolysis and binding to "walk" "hand over hand"
motor proteins like kinesins and dyneins
move toward the positive end of microtubules
kinesins
move toward the negative end of microtubules
dyneins
examples of stable microtubules
cilia and flagella
"9+2"
9 doublet microtubules arranged around a pair of single microtubules
helps cilia and flagella move in a bending motion
ciliary dynein
what dynein uses to generate sliding force
ATP
how cilia/flagella motion can make a bending motion instead of sliding
linker proteins
Epidermolysis bullosa therapeutic target
Filsuvez, birch bark extract
listeriosis
bacterial infection from food contamination, manipulates actin filaments (zoomies)
function of actin
supports cell surface and allows for cell motility
influences strength of binding in actin filaments
ATP hydrolysis
how actin filaments are structurally similar to microtubules
both contain + and - ends
treadmilling
rate of addition on + end in actin filaments is equal to the rate of disassembly on - end
what a concentrated layer of actin in the cell cortex does
supports the plasma membrane
3 steps of actin motility
cell protrusions, protrusions adhere to surface, remainder of cell is pulled along
lamellipodia/filopodia
extensions of actin with positive end oriented toward the PM
how lamellipodia stick to favorable surfaces
they use integrins
myosin 1
similar to kinesin, has head and tail, functions to transport vesicles or change PM shape
myosin 2
used for muscle contraction
contractile unit of muscle cells
sarcomere
myosin filaments
clusters of myosin 2 molecules