XMAP215 is a microtubule nucleation factor that functions synergistically with the γ-tubulin ring complex.

TitleXMAP215 is a microtubule nucleation factor that functions synergistically with the γ-tubulin ring complex.
Publication TypeJournal Article
Year of Publication2018
AuthorsThawani, A, Kadzik, RS, Petry, S
JournalNat Cell Biol
Volume20
Issue5
Pagination575-585
Date Published2018 May
ISSN1476-4679
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.

DOI10.1038/s41556-018-0091-6
Alternate JournalNat. Cell Biol.
PubMed ID29695792
PubMed Central IDPMC5926803
Grant ListDP2 GM123493 / GM / NIGMS NIH HHS / United States
F32 GM119195 / GM / NIGMS NIH HHS / United States