Actin and Microtubules

What is the actin monomer?

G-Actin

What are the Microtubule monomers?

Alpha-tubulin and Beta-tubulin

What is the actin plus end also called?

Barbed

What is the actin minus end also called?

Pointed

What nucleator makes linear actin?

Formin

What nucleator makes linear microtubules?

y-Tubulin

Formin’s microtubule equivalent

Y-tubulin

What nucleator makes branched actin?

Arp2/3

What nucleator makes branched microtubules?

Augmin

What is augmin’s actin counterpart?

Arp2/3

What two elongators enhance actin growth?

Formin and Profilin

What elongator enhances microtubule growth?

XMAP215

XMAP215’s actin counterpart

Formin and Profilin

What elongators block actin elongation?

Thymosin and capping protein

What elongators block microtubule elongation?

Kinesin-13 and Stathmin

Thymosin and Capping Protein’s microtubule equivalents

Kinesin-13 and Stathmin

What crosslinkers make actin bundles?

Fascin and a-actinin

What crosslinkers make microtubule bundles?

MAP2 and tau

What is the microtubule equivalent of fascin and a-actinin?

MAP2 and tau

What crosslinker makes actin meshworks?

Filamin

What crosslinker makes microtubule meshworks?

None of them

What depolymerizes actin?

Cofilin

What depolymerizes a microtubule?

Katanin

What is katanin’s actin equivalent?

Cofilin

Are filopodia made by actin or microtubules?

Actin

Are lamellipodia made of actin or microtubules?

Actin

Are stress fibers made of actin or microtubules?

Actin

Are cilia made of actin or microtubules?

Microtubules

What is an actin regulator?

Rho-family GTPases

What is a microtubule regulator?

Trick question

What does the Rho GTPase Cdc42 do?

Induces tight actin bundling at the cell edge to create filopodia

What does the Rho GTPase Rac do?

Recruits Arp2/3 at the cell edge to create lamellipodia

What does the Rho GTPase “Rho” do?

Induces stress fiber formation by activating formins to make an unbranched actin bundle