Page 214 - Color Atlas of Biochemistry

Cytoskeleton 205

A. Actin
Associates Dissociates
more easily more easily
ATP ADP
Polymerization P
8 nm i
Depolymerization
F-actin
helical polymer G-Actin ATP Slow ADP
P
microfilament (detail) monomers hydrolysis i
42 kDa

Phalloidin
Cytochalasin

(–) End: dissociation (+) End: polymerization
favored favored

B. Intermediate filaments
IF Proteins:
Cytokeratins
Dimer Desmin
Vimentin
Glial fibrillary
Superhelical structure acidic protein
Neurofilaments
Lamins
Tetramer

Protofilament

Intermediate
filament 10 nm

C. Tubulins
binds GTP and 25 nm
slowly hydrolyzes it

αβ Protofilament
Tubulin Microtubule
53 and 55 kDa (cylindrical polymer)
heterodimer

Plant
alkaloids:
Vinblastine,
vincristine,
colchicine
Taxol
(–) End: stabilized by binding (+) End: grows
to the centromere or shortens

Koolman, Color Atlas of Biochemistry, 2nd edition © 2005 Thieme
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