Skip to Main content Skip to Navigation
Journal articles

Ran GTPase promotes oocyte polarization by regulating ERM (Ezrin/Radixin/Moesin) inactivation.

Abstract : Asymmetric meiotic divisions in mammalian oocytes are driven by the eccentric positioning of the spindle, along with a dramatic reorganization of the overlying cortex, including a loss of microvilli and formation of a thick actin cap. Actin polarization relies on a Ran-GTP gradient centered on metaphase chromosomes; however, the downstream signaling cascade is not completely understood. In a recent study, we have shown that Ran promotes actin cap formation via the polarized activation of Cdc42. The related GTPase Rac is also activated in a polarized fashion in the oocyte cortex and co-localizes with active Cdc42. In other cells, microvilli collapse can be triggered by inactivation of the ERM (Ezrin/Radixin/Moesin) family of actin-membrane crosslinkers under the control of Rac. Accordingly, we show here that Ran-GTP promotes a substantial loss of phosphorylated ERMs in the cortex overlying the spindle in mouse oocytes. However, this polarized phospho-ERM exclusion zone was unaffected by Rac or Cdc42 inhibition. Therefore, we suggest that Ran activates two distinct pathways to regulate actin cap formation and microvilli disassembly in the polarized cortex of mouse oocytes. The possibility of a crosstalk between Rho GTPase and ERM signaling and a role for ERM inactivation in promoting cortical actin dynamics are also discussed.
Document type :
Journal articles
Complete list of metadata

Cited literature [45 references]  Display  Hide  Download
Contributor : Nathalie Coval Connect in order to contact the contributor
Submitted on : Tuesday, December 10, 2013 - 1:13:06 PM
Last modification on : Thursday, January 14, 2021 - 11:21:20 AM
Long-term archiving on: : Monday, March 10, 2014 - 10:50:20 PM


Files produced by the author(s)




Benoit Dehapiot, Guillaume Halet. Ran GTPase promotes oocyte polarization by regulating ERM (Ezrin/Radixin/Moesin) inactivation.. Cell Cycle, Taylor & Francis, 2013, 12 (11), pp.1672-8. ⟨10.4161/cc.24901⟩. ⟨hal-00866026⟩



Record views


Files downloads