CLIP-170 tracks growing microtubule ends by dynamically recognizing composite EB1/tubulin-binding sites.
J Cell Biol
; 183(7): 1223-33, 2008 Dec 29.
Article
em En
| MEDLINE
| ID: mdl-19103809
ABSTRACT
The microtubule cytoskeleton is crucial for the internal organization of eukaryotic cells. Several microtubule-associated proteins link microtubules to subcellular structures. A subclass of these proteins, the plus end-binding proteins (+TIPs), selectively binds to the growing plus ends of microtubules. Here, we reconstitute a vertebrate plus end tracking system composed of the most prominent +TIPs, end-binding protein 1 (EB1) and CLIP-170, in vitro and dissect their end-tracking mechanism. We find that EB1 autonomously recognizes specific binding sites present at growing microtubule ends. In contrast, CLIP-170 does not end-track by itself but requires EB1. CLIP-170 recognizes and turns over rapidly on composite binding sites constituted by end-accumulated EB1 and tyrosinated alpha-tubulin. In contrast to its fission yeast orthologue Tip1, dynamic end tracking of CLIP-170 does not require the activity of a molecular motor. Our results demonstrate evolutionary diversity of the plus end recognition mechanism of CLIP-170 family members, whereas the autonomous end-tracking mechanism of EB family members is conserved.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Tubulina (Proteína)
/
Proteínas Associadas aos Microtúbulos
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Microtúbulos
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Proteínas de Neoplasias
Limite:
Animals
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Humans
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article