Lecture 14 - Cytoskeleton_ tubulin (1)

What are the three classes of cytoskeletal filaments?

Microfilaments, microtubules, and intermediate filaments.

What is the primary protein that makes up microtubules?

Tubulin.

What are the subunits that form a microtubule?

Alpha-tubulin and beta-tubulin heterodimers.

What term describes the process by which microtubules alternate between growth and shrinkage?

Dynamic instability.

What structural feature gives microtubules their polarity?

The orientation of their subunits.

How are microtubules organized in animal cells?

They are generally nucleated from the microtubule-organizing center (MTOC).

What is a catastrophe in the context of microtubule dynamics?

The change from growth to shrinkage.

What role do microtubule associated proteins (MAPs) play?

They bind and stabilize microtubules.

What is the function of the centrosome in relation to microtubules?

The centrosome is a microtubule-organizing center that nucleates and organizes microtubules.

Which phase of microtubule dynamics follows the lag phase?

Elongation phase.

What effect does GTP hydrolysis have on microtubules?

It changes the conformation of subunits and can cause protofilaments to curve, destabilizing the microtubule.

What is the significance of the γ-tubulin ring complex?

It helps in the nucleation of microtubules.

What is the term for the microtubule plus end?

The end that grows and shrinks more rapidly than the minus end.

Which proteins are examples of intermediate filaments?

Desmin, Lamin, Keratin.

What is a microtubule built from?

13 parallel protofilaments composed of αβ-tubulin heterodimers.

What is the consequence of Tau mutations in relation to health?

They can cause neurodegenerative diseases like Alzheimer's disease.

What determines the organization and spacing of microtubule bundles?

MAP2 and Tau.

What is the process of microtubule nucleation?

The interaction of several tubulin molecules to form a microtubule seed.

What stabilizes the microtubule wall structure during assembly?

The addition of GTP-tubulin at the plus end.

What is meant by the term 'rescue' in microtubule dynamics?

The change from shrinkage to growth.