Cytoskeleton general Flashcards
(16 cards)
What are the purposes of the cytoskeleton?
Shape
Movement
Strength
Feeding
What are the main components of the cytoskeleton?
Microtubules
Microfilaments
Intermediate filaments
What are microtubules made of ?
13 Tubulin (alpha-beta)
What is the purpose of mictorubules?
Long range transport of organelles
Assemble of mitotic spindle and chromosome segregation
What binds to tubulin?
GTP
What are microfilaments made of ?
Actin subunits
What binds to actin ?
ATP
What is the purpose of microfilaments?
Contractile machinery
membrane protrusion
cell cortex stabilisation
short range movement of organelles
cell motility
What characteristic do microt. and microfil. have in common?
They are both polarised and highly dinamic
Microtubules are tracks for…
Dyneins and Kinesins
Microfilaments are tracks for…
myosin
What drugs inhibit microtubule formation and how
Colchicine: binds tubulin dimers and inhibits polymerisation
Taxol: binds and stabilises microtubules against deploymerisation
What is the purpose of intermediate filaments?
structural support to the nuclear membrane (lamina)
structural integrity to cells and tissues
structural barrier functions in skin, hair and nails.
How do intermediate filaments associate?
IF proteins form parallel dimers.
A tetramer is formed by anti-parallel, staggered side-by-side aggregation of two identical dimers.
Tetramers aggregate end to end and laterally to form a protofibril
How are IF different compared to microt. and microf.?
They are less dynamic and not polarised.
How are microt. and microf. different in making the structure?
Microt. only grow at one end whereas microfil. are known to grow by tread milling action so both ends are involved.
