A kinesin-13 mutant catalytically depolymerizes microtubules in ADP.
J Cell Biol
; 183(4): 617-23, 2008 Nov 17.
Article
em En
| MEDLINE
| ID: mdl-19001124
ABSTRACT
The kinesin-13 motor protein family members drive the removal of tubulin from microtubules (MTs) to promote MT turnover. A point mutation of the kinesin-13 family member mitotic centromere-associated kinesin/Kif2C (E491A) isolates the tubulin-removal conformation of the motor, and appears distinct from all previously described kinesin-13 conformations derived from nucleotide analogues. The E491A mutant removes tubulin dimers from stabilized MTs stoichiometrically in adenosine triphosphate (ATP) but is unable to efficiently release from detached tubulin dimers to recycle catalytically. Only in adenosine diphosphate (ADP) can the mutant catalytically remove tubulin dimers from stabilized MTs because the affinity of the mutant for detached tubulin dimers in ADP is low relative to lattice-bound tubulin. Thus, the motor can regenerate for further cycles of disassembly. Using the mutant, we show that release of tubulin by kinesin-13 motors occurs at the transition state for ATP hydrolysis, which illustrates a significant divergence in their coupling to ATP turnover relative to motile kinesins.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tubulina (Proteína)
/
Difosfato de Adenosina
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Cinesinas
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Substituição de Aminoácidos
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Mutação de Sentido Incorreto
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Microtúbulos
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Cell Biol
Ano de publicação:
2008
Tipo de documento:
Article