Signaling network crosstalk in human pluripotent cells: A Smad2/3-regulated switch that controls the balance between self-renewal and differentiation

Academic Article

Abstract

  • A general mechanism for how intracellular signaling pathways in human pluripotent cells are coordinated and how they maintain self-renewal remain to be elucidated. In this report, we describe a signaling mechanism where PI3K/Akt activity maintains self-renewal by restraining prodifferentiation signaling through suppression of the Raf/Mek/Erk and canonical Wnt signaling pathways. When active, PI3K/Akt establishes conditions where Activin A/Smad2,3 performs a pro-self-renewal function by activating target genes, including Nanog. When PI3K/Akt signaling is low, Wnt effectors are activated and function in conjunction with Smad2,3 to promote differentiation. The switch in Smad2,3 activity after inactivation of PI3K/Akt requires the activation of canonical Wnt signaling by Erk, which targets Gsk3β. In sum, we define a signaling framework that converges on Smad2,3 and determines its ability to regulate the balance between alternative cell states. This signaling paradigm has far-reaching implications for cell fate decisions during early embryonic development. © 2012 Elsevier Inc.
  • Published In

  • Cell Stem Cell  Journal
  • Digital Object Identifier (doi)

    Author List

  • Singh AM; Reynolds D; Cliff T; Ohtsuka S; Mattheyses AL; Sun Y; Menendez L; Kulik M; Dalton S
  • Start Page

  • 312
  • End Page

  • 326
  • Volume

  • 10
  • Issue

  • 3