Stathmin/Op18 Phosphorylation Is Regulated by Microtubule Assembly
AUTOR(ES)
Küntziger, Thomas
FONTE
The American Society for Cell Biology
RESUMO
Stathmin/Op 18 is a microtubule (MT) dynamics-regulating protein that has been shown to have both catastrophe-promoting and tubulin-sequestering activities. 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 investigated whether MT assembly itself could control phosphorylation of stathmin/Op18 and thus its MT-destabilizing activity. We found that MT nucleation by centrosomes from Xenopus sperm or somatic cells and MT assembly promoted by dimethyl sulfoxide or paclitaxel induced stathmin/Op18 hyperphosphorylation in Xenopus egg extracts, leading to new stathmin/Op18 isoforms phosphorylated 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 mediated by an activity associated to the MTs, and that it is responsible for the stathmin/Op18 hyperphosphorylation reported to be induced by the addition of “mitotic chromatin.” Our results suggest the existence of a positive feedback loop, which could represent a novel mechanism contributing to MT network control.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=30954Documentos Relacionados
- Model for stathmin/OP18 binding to tubulin
- Deciphering the Cellular Functions of the Op18/Stathmin Family of Microtubule-Regulators by Plasma Membrane-targeted Localization
- Phosphorylation disrupts the central helix in Op18/stathmin and suppresses binding to tubulin
- Op18/stathmin caps a kinked protofilament-like tubulin tetramer
- Oncoprotein 18 is a phosphorylation-responsive regulator of microtubule dynamics.