title: The ubiquitin ligase mLin41 temporally promotes neural progenitor cell maintenance through FGF signaling.
abstract: How self-renewal versus differentiation of neural progenitor cells is temporally controlled during early development remains ill-defined. We show that mouse Lin41 (mLin41) is highly expressed in neural progenitor cells and its expression declines during neural differentiation. Loss of mLin41 function in mice causes reduced proliferation and premature differentiation of embryonic neural progenitor cells. mLin41 was recently implicated as the E3 ubiquitin ligase that mediates degradation of Argonaute 2 (AGO2), a key effector of the microRNA pathway. However, our mechanistic studies of neural progenitor cells indicate mLin41 is not required for AGO2 ubiquitination or stability. Instead, mLin41-deficient neural progenitors exhibit hyposensitivity for fibroblast growth factor (FGF) signaling. We show that mLin41 promotes FGF signaling by directly binding to and enhancing the stability of Shc SH2-binding protein 1 (SHCBP1) and that SHCBP1 is an important component of FGF signaling in neural progenitor cells. Thus, mLin41 acts as a temporal regulator to promote neural progenitor cell maintenance, not via the regulation of AGO2 stability, but through FGF signaling.
authors.affiliation: Howard Hughes Medical Institute, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital Colorado, Aurora, CO 80045, USA. jianfu.chen@ucdenver.edu
authors.forename: Jianfu
authors.initials: J
authors.lastname: Chen
authors.forename: Fan
authors.initials: F
authors.lastname: Lai
authors.forename: Lee
authors.initials: L
authors.lastname: Niswander
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D051379:Mice; D058953:Neural Stem Cells / Q000166:cytology* / Q000201:enzymology; D055550:Protein Stability; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C526735:Ago2 protein, mouse; D060565:Argonaute Proteins; C511366:LIN-41 protein, mouse; D014157:Transcription Factors; D005346:Fibroblast Growth Factors; D044767:Ubiquitin-Protein Ligases