title: RELB Alters Proliferation of Human Pluripotent Stem Cells via IMP3- and LIN28-Mediated Modulation of the Expression of IGF2 and Other Cell-Cycle Regulators.
abstract: The molecular mechanisms that orchestrate the exit from pluripotency, cell cycle progression, and lineage-specific differentiation in human pluripotent stem cells (hPSCs) are poorly understood. RELB, a key protein in the noncanonical nuclear factor-kappaB (NFκB) signaling pathway, was previously implicated in controlling the switch between human embryonic stem cell (hESC) proliferation and differentiation. Here, we show that RELB enhances the proliferation of hESCs and human-induced pluripotent stem cells (hiPSCs) without affecting their pluripotency. We demonstrate that RELB does this by interacting with two RNA-binding proteins LIN28A and IMP3 (IGF2 mRNA-binding protein 3); further, these interactions control mRNA levels and protein expression of insulin-like growth factor 2 (IGF2) and key cell-cycle genes. Finally, after stress, these proteins co-localize in stress granules in hESCs and iPSCs. Our data identify RELB as a novel regulator of hPSC proliferation, and suggest a new function for RELB, in addition to its widely accepted role as a transcription factor, that involves recruitment of IMP3 and LIN28 to the cytosolic mRNA translation-control domains for post-transcriptional modulation of IGF2 and cell-cycle gene expression.
authors: 1 Stem Cell Engineering Group, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland , St. Lucia, QLD, Australia .
authors: Nilay Yogeshkumar
authors: NY
authors: Thakar
authors: 1 Stem Cell Engineering Group, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland , St. Lucia, QLD, Australia .
authors: Dmitry Alexander
authors: DA
authors: Ovchinnikov
authors: 2 Protein Discovery Centre, QIMR Berghofer Medical Research Institute , Herston, QLD, Australia .
authors: Marcus Lachlan
authors: ML
authors: Hastie
authors: 2 Protein Discovery Centre, QIMR Berghofer Medical Research Institute , Herston, QLD, Australia .
authors: Jeffrey
authors: J
authors: Gorman
authors: 1 Stem Cell Engineering Group, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland , St. Lucia, QLD, Australia .
authors: Ernst Jurgen
authors: EJ
authors: Wolvetang
mesh_terms: D002460:Cell Line; D049109:Cell Proliferation; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism* / Q000502:physiology; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051841:Transcription Factor RelB / Q000235:genetics / Q000378:metabolism*
chemical_list: C035170:IGF2 protein, human; C498780:IGF2BP3 protein, human; C000715187:Lin28A protein, human; C497593:RELB protein, human; D016601:RNA-Binding Proteins; D051841:Transcription Factor RelB; D007335:Insulin-Like Growth Factor II