IGF-1 Activates a cilium-localized noncanonical gβγ signaling pathway that regulates cell-cycle progression

Celine Yeh, Aiqun Li, Jen Zen Chuang, Masaki Saito, Alfredo Cáceres, Ching Hwa Sung

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)


Primary cilia undergo cell-cycle-dependent assembly and disassembly. Emerging data suggest that ciliary resorption is a checkpoint for S phase reentry and that the activation of phospho(T94)Tctex-1 couples these two events. However, the environmental cues and molecular mechanisms that trigger these processes remain unknown. Here, we show that insulin-like growth-1 (IGF-1) accelerates G1-S progression by causing cilia to resorb. The mitogenic signals of IGF-1 are predominantly transduced through IGF-1 receptor (IGF-1R) on the cilia of fibroblasts and epithelial cells. At the base of the cilium, phosphorylated IGF-1R activates an AGS3-regulated Gβγ signaling pathway that subsequently recruits phospho(T94)Tctex-1 to the transition zone. Perturbing any component of this pathway in cortical progenitors induces premature neuronal differentiation at the expense of proliferation. These data suggest that during corticogenesis, a cilium-transduced, noncanonical IGF-1R-Gβγ-phospho(T94)Tctex-1 signaling pathway promotes the proliferation of neural progenitors through modulation of ciliary resorption and G1 length.

Original languageEnglish
Pages (from-to)358-368
Number of pages11
JournalDevelopmental cell
Issue number4
Publication statusPublished - 2013 Aug 26

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Developmental Biology
  • Cell Biology


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