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XB-ART-54841
Nat Cell Biol January 1, 2018; 20 (5): 575-585.
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XMAP215 is a microtubule nucleation factor that functions synergistically with the γ-tubulin ring complex.

Thawani A , Kadzik RS , Petry S .


Abstract
How microtubules (MTs) are generated in the cell is a major question in understanding how the cytoskeleton is assembled. For several decades, γ-tubulin has been accepted as the universal MT nucleator of the cell. Although there is evidence that γ-tubulin complexes are not the sole MT nucleators, identification of other nucleation factors has proven difficult. Here, we report that the well-characterized MT polymerase XMAP215 (chTOG/Msps/Stu2p/Alp14/Dis1 homologue) is essential for MT nucleation in Xenopus egg extracts. The concentration of XMAP215 determines the extent of MT nucleation. Even though XMAP215 and the γ-tubulin ring complex (γ-TuRC) possess minimal nucleation activity individually, together, these factors synergistically stimulate MT nucleation in vitro. The amino-terminal TOG domains 1-5 of XMAP215 bind to αβ-tubulin and promote MT polymerization, whereas the conserved carboxy terminus is required for efficient MT nucleation and directly binds to γ-tubulin. In summary, XMAP215 and γ-TuRC together function as the principal nucleation module that generates MTs in cells.

PubMed ID: 29695792
Article link: Nat Cell Biol
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: ckap5

References [+] :
, The noncoding explosion. 2015, Pubmed