Lazarus... Holzbaur. Plos. Take 2

Question 1

Why is transport on microtubules particularly vulnerable to disruption in axons/

Answer 1

1. Cells are long-lived. 2. Axon tracks extend up to one meter.

Question 2

What is the rate-limiting step of microtubule formation?

Answer 2

Nucleation of soluble tubulin catalyzed by gamma-TURC enriched at the centrosome.

Question 3

MAPS

Answer 3

Microtubule associated proteins

Question 4

+TIPS

Answer 4

A spatially specialized group of MAPS that are plus end tracking proteins

Question 5

What is the main goal of this paper?

Answer 5

Investigate whether p150glued modifies microtubule dynamics and affects catastrophe

Question 6

Arp1

Answer 6

Forms the base of the dynactin complex

Question 7

Paclitaxel

Answer 7

Stabilizes microtubules

Question 8

What are two constructs that were created for the purposes of this paper?

Answer 8

P150-NT – has the N-terminal, and the CAP-Gly domain, but no dimerization domain. P150-NT-GCN4 – has a dimerization domain, N terminal CAP-gly, and basic microtubule binding domains. GCN4 replaces the first coiled coil.

Question 9

What does increased light scattering indicate?

Answer 9

Increased microtubule polymerization

Question 10

TIRF Microscopy

Answer 10

Total internal reflection fluorescence microscopy. The main idea is to reduce background fluorescence so that there is a higher signal to noise ratio. Selectively excites fluorophores in a restricted region adjacent to the glass-H2O interface. Only penetrates 100 nm. Can be used to observe fluorescence of a single molecule.

Question 11

Doublecortin

Answer 11

This molecule is encoded by the DCX gene. It is another neuronal MAP. It is also called lissencephalin-x. It is another protein whose absence leads to lissencephaly (in addition to lis1) and it is also involved in neuronal migration (I think).

Question 12

Does addition of doublecortin lead to light scattering?

Answer 12

Yes; doublecortin leads to microtubule polymerization, which promotes light scattering

Question 13

What is one way to measure microtubule polymerization?

Answer 13

Light scattering

Question 14

What did this study find regarding light scattering for monomers of p150 versus dimers? (p150-NT versus p150-NT-GCN4?)

Answer 14

Dimers increased microtubule polymerization, measured by light scattering; monomers did not

Question 15

Does p150 need EB1 to promote microtubule formation?

Answer 15

According to this paper, no; they are independent of each other.