The PI3K/Akt1 pathway enhances steady-state levels of FANCL

Kim-Hien Dao, Michael D. Rotelli, Brieanna R. Brown, Jane E. Yates, Juha Rantala, Cristina Tognon, Jeffrey Tyner, Brian Druker, Grover C. Bagby

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Fanconi anemia hematopoietic stem cells display poor self-renewal capacity when subjected to a variety of cellular stress. This phenotype raises the question of whether the Fanconi anemia proteins are stabilized or recruited as part of a stress response and protect against stem cell loss. Here we provide evidence that FANCL, the E3 ubiquitin ligase of the Fanconi anemia pathway, is constitutively targeted for degradation by the proteasome. We confirm biochemically that FANCL is polyubiquitinated with Lys-48-linked chains. Evaluation of a series of N-terminal-deletion mutants showed that FANCL's E2-like fold may direct ubiquitination. In addition, our studies showed that FANCL is stabilized in a complex with axin1 when glycogen synthase kinase-3β is overexpressed. This result leads us to investigate the potential regulation of FANCL by upstream signaling pathways known to regulate glycogen synthase kinase-3β. We report that constitutively active, myristoylated-Akt increases FANCL protein level by reducing polyubiquitination of FANCL. Two-dimensional PAGE analysis shows that acidic forms of FANCL, some of which are phospho-FANCL, are not subject to polyubiquitination. These results indicate that a signal transduction pathway involved in self-renewal and survival of hematopoietic stem cells also functions to stabilize FANCL and suggests that FANCL participates directly in support of stem cell function.

Original languageEnglish (US)
Pages (from-to)2582-2592
Number of pages11
JournalMolecular Biology of the Cell
Volume24
Issue number16
DOIs
StatePublished - Aug 15 2013

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Glycogen Synthase Kinase 3
Fanconi Anemia
Fanconi Anemia Complementation Group L Protein
Hematopoietic Stem Cells
Phosphatidylinositol 3-Kinases
Fanconi Anemia Complementation Group Proteins
Stem Cells
Ubiquitin-Protein Ligases
Ubiquitination
Proteasome Endopeptidase Complex
Signal Transduction
Phenotype

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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The PI3K/Akt1 pathway enhances steady-state levels of FANCL. / Dao, Kim-Hien; Rotelli, Michael D.; Brown, Brieanna R.; Yates, Jane E.; Rantala, Juha; Tognon, Cristina; Tyner, Jeffrey; Druker, Brian; Bagby, Grover C.

In: Molecular Biology of the Cell, Vol. 24, No. 16, 15.08.2013, p. 2582-2592.

Research output: Contribution to journalArticle

Dao K-H, Rotelli MD, Brown BR, Yates JE, Rantala J, Tognon C et al. The PI3K/Akt1 pathway enhances steady-state levels of FANCL. Molecular Biology of the Cell. 2013 Aug 15;24(16):2582-2592. https://doi.org/10.1091/mbc.E13-03-0144
Dao, Kim-Hien ; Rotelli, Michael D. ; Brown, Brieanna R. ; Yates, Jane E. ; Rantala, Juha ; Tognon, Cristina ; Tyner, Jeffrey ; Druker, Brian ; Bagby, Grover C. / The PI3K/Akt1 pathway enhances steady-state levels of FANCL. In: Molecular Biology of the Cell. 2013 ; Vol. 24, No. 16. pp. 2582-2592.
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