A designed ankyrin repeat protein selected to bind to tubulin caps the microtubule plus end.
Proc Natl Acad Sci U S A
; 109(30): 12011-6, 2012 Jul 24.
Article
em En
| MEDLINE
| ID: mdl-22778434
ABSTRACT
Microtubules are cytoskeleton filaments consisting of αß-tubulin heterodimers. They switch between phases of growth and shrinkage. The underlying mechanism of this property, called dynamic instability, is not fully understood. Here, we identified a designed ankyrin repeat protein (DARPin) that interferes with microtubule assembly in a unique manner. The X-ray structure of its complex with GTP-tubulin shows that it binds to the ß-tubulin surface exposed at microtubule (+) ends. The details of the structure provide insight into the role of GTP in microtubule polymerization and the conformational state of tubulin at the very microtubule end. They show in particular that GTP facilitates the tubulin structural switch that accompanies microtubule assembly but does not trigger it in unpolymerized tubulin. Total internal reflection fluorescence microscopy revealed that the DARPin specifically blocks growth at the microtubule (+) end by a selective end-capping mechanism, ultimately favoring microtubule disassembly from that end. DARPins promise to become designable tools for the dissection of microtubule dynamic properties selective for either of their two different ends.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Tubulina (Proteína)
/
Modelos Moleculares
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Repetição de Anquirina
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Complexos Multiproteicos
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Microtúbulos
Limite:
Animals
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article