Accessory Proteins

Question 1

ARP Complex

Answer 1

Nucleates, Minus End. Actin related protein nucleates assembly to form weblike, highly branched chains and remains associated with minus end

Works best when cross linked

Question 2

Formin

Answer 2

Nucleates, Plus End. Nucleates assembly of long, unbranched chains + remains associated with growing plus end

Question 3

Thymosin

Answer 3

Disassembly. Binds actin subunits, prevents assembly

Question 4

Prolifin

Answer 4

Assembly. Binds actin subunits, speeds elongation

Question 5

Tropomodulin

Answer 5

Stabilize. Prevents assembly and disassembly at monus end-stabilized actin filament for long lived filament stabilization

Question 6

Tropomyosin

Answer 6

Stabilizes filament; prevents binding with others

Question 7

Capping protein

Answer 7

Prevents assembly/disassembly at plus end

Question 8

Gelsolin

Answer 8

Severs actin filaments and binds to PLUS end

Question 9

Cofilin

Answer 9

Binds ADP-actin filaments and binds to plus end

Question 10

Alpha Actinin

Answer 10

Bundling Protein; cross links actin filaments in to parallel array (looser)

Question 11

Fimbrin

Answer 11

Bundling Protein; cross links actin filaments in to parrallel array (tighter)

Question 12

Filamin

Answer 12

Forms gel-like structure; holds actin filaments together at large angles to create a looser meshwork. Allow crawling

Question 13

Spectrin

Answer 13

Attaches cytoskeleton to membrane; if defective leads to hemolytic anemia and Hereditary Spherocytosis

Question 14

ERM Family

Answer 14

Attaches cytoskeleton to membrane by mediating between actin and plasma membrane

Question 15

What are the three main groups of microtubule accessory proteins?

Answer 15

tubulin, microtubules and filament cross linking

Question 16

Microtubule subunits include ____ and___ that stem from

Answer 16

Alpha and Beta Tubulin; Microtubule organizing center