Stathmin/Op18 phosphorylation is regulated by microtubule assembly

Citation
T. Kuntziger et al., Stathmin/Op18 phosphorylation is regulated by microtubule assembly, MOL BIOL CE, 12(2), 2001, pp. 437-448
Citations number
49
Categorie Soggetti
Cell & Developmental Biology
Journal title
MOLECULAR BIOLOGY OF THE CELL
ISSN journal
10591524 → ACNP
Volume
12
Issue
2
Year of publication
2001
Pages
437 - 448
Database
ISI
SICI code
1059-1524(200102)12:2<437:SPIRBM>2.0.ZU;2-U
Abstract
Stathmin/Op 18 is a microtubule (MT) dynamics-regulating protein that has b een shown to have both catastrophe-promoting and tubulin-sequestering activ ities. The level of stathmin/Op18 phosphorylation was proved both in vitro and in vivo to be important in modulating its MT-destabilizing activity. To understand the in vivo regulation of stathmin/Op18 activity, we investigat ed whether MT assembly itself could control phosphorylation of stathmin/Op1 8 and thus its MT-destabilizing activity. We found that MT nucleation by ce ntrosomes from Xenopus sperm or somatic cells and MT assembly promoted by d imethyl sulfoxide or paclitaxel induced stathmin/Op18 hyperphosphorylation. in Xenopus egg extracts, leading to new stathmin/Op18 isoforms phosphoryla ted on Ser 16. The MT-dependent phosphorylation of stathmin/Op18 took place in interphase extracts as well, and was also observed in somatic cells. We show that the MT-dependent phosphorylation of stathmin/Op18 on Ser 16 is m ediated by an activity associated to the MTs, and that it is responsible fo r the stathmin/Op18 hyperphosphorylation reported to be induced by the addi tion of "mitotic chromatin." Our results suggest the existence of a positiv e feedback loop, which could represent a novel mechanism contributing to MT network control.