INHIBITOR-2 INDUCED M-PHASE ARREST IN XENOPUS CYCLING EGG EXTRACTS IS DEPENDENT ON MAPK ACTIVATION

作者：Khandani Arian^*; Mohtashami Mahmood; Camirand Anne

来源：Cellular and Molecular Biology Letters, 2011, 16(4): 669-688.

DOI：10.2478/s11658-011-0030-z

• Inhibitor-2
• PP-1 phosphatase
• MAPK kinase
• p90Rsk
• M-phase arrest
• Xenopus cycling egg extract

The evolutionarily-conserved protein phosphatase 1 (PP1) plays a central role in dephosphorylation of phosphoproteins during the M phase of the cell cycle. We demonstrate here that the PP1 inhibitor inhibitor-2 protein (Inh-2) induces an M-phase arrest in Xenopus cycling egg extracts. Interestingly, the characteristics of this M-phase arrest are similar to those of mitogen-activated protein kinase (p42MAPK)-induced M-phase arrest. This prompted us to investigate whether Inh-2-induced M-phase arrest was dependent on activation of the p42MAPK pathway. We demonstrate here that MAPK activity is required for Inh-2-induced M-phase arrest, as inhibition of MAPK by PD98059 allowed cycling extracts to exit M phase, despite the presence of Inh-2. We next investigated whether Inh-2 phosphorylation by the MAPK pathway was required to induce an M-phase arrest. We discovered that while p90Rsk (a MAPK protein required for M-phase arrest) is able to phosphorylate Inh-2, this phosphorylation is not required for Inh-2 function. Overall, our results suggest a novel mechanism linking p42MAPK and PP1 pathways during M phase of the cell cycle.

• 出版日期2011-12
• 单位河北医科大学