The Cytoskeleton Flashcards
What are the X2 different types of actin?
One is a polymer of the other, but which is which?
F-actin is a polymer of G-actin
F = filamentous
G = globular
What is the shape of the monomer G-actin?
Butterfly shaped
How do actin filaments form?
How do they degrade?
G-actin requires ATP to polymerise
It can bind to either end, but the filament has a positive and negative end and polymerisation occurs more rapidly at the positive end
As time passes ATP is hydrolysed to ADP which increases susceptibility to depolarisation
How do intermediate filaments form?
What is their monomer?
Their monomers are intermediate filament proteins
X2 IF proteins form a helical dimer
X2 helical dimers form X1 IF unit tetramer
What is the monomer of microtubules?
What are each of these made up of?
Which end is negative and which is positive?
Tubulin
= X1 alpha Tubulin = negative
= X1 beta Tubulin = positive
How many molecules of Tubulin make up the microtubule circumference?
X13
How do microtubules assemble?
Does this require energy?
How do they degrade?
Tubulin monomers bind to GTP and join the GTP rich cap (+ve end) of the microtubule polymer
Over time the GTP hydrolyses to GDP and these GDP bound monomers dissociate rapidly
What protein links all X3 of these cytoskeleton components together?
Plectin
What type of structures show actin based movement?
Lamellipodia
Through what do lamellipodia adhere to the ECM?
What protein do they use to attach themselves to the ECM?
Focal contact junctions or focal adhesions
Integrins
What structures use microtubule based movements?
Cilia
What microtubule associated protein attaches to X1 microtubule of one pair and one of the neighbouring pair to climb up it in order to create the cilia style movements?
Dyenin
What of the X3 protein filaments are involved in the movement of synaptic vesicles and other intracellular cargo along their filaments?
Which associated proteins aid in this function? Name X2 and state which end of the protein filament they transport towards.
Microtubules
Dyenin = towards the negative end
Kinesin = towards the positive end
What is the name given to dyenin and kinesin relating to the fact that they do not become un-attached from the microtubule when transporting molecules?
Processive motor proteins
Name a non-processive motor protein.
Why is it non-processive?
Myosin
During its movements it detaches
