We have previously shown that the insulin-like growth factor 1 receptor (IGF-1R) translocates to the cell nucleus, where it binds to enhancer-like regions and increases gene transcription. Further studies have demonstrated that nuclear IGF-1R (nIGF-1R) physically and functionally interacts with some nuclear proteins, i.e. the lymphoid enhancer-binding factor 1 (Lef1), histone H3, and Brahma-related gene-1 proteins. In this study, we identified the proliferating cell nuclear antigen (PCNA) as a nIGF-1R-binding partner. PCNA is a pivotal component of the replication fork machinery and a main regulator of the DNA damage tolerance (DDT) pathway. We found that IGF-1R interacts with and phosphorylates PCNA in human embryonic stem cells and other cell lines. In vitro MS analysis of PCNA co-incubated with the IGF-1R kinase indicated tyrosine residues 60, 133, and 250 in PCNA as IGF-1R targets, and PCNA phosphorylation was followed by mono- and polyubiquitination. Co-immunoprecipitation experiments suggested that these ubiquitination events may be mediated by DDT-dependent E2/E3 ligases (e.g. RAD18 and SHPRH/HLTF). Absence of IGF-1R or mutation of Tyr-60, Tyr-133, or Tyr-250 in PCNA abrogated its ubiquitination. Unlike in cells expressing IGF-1R, externally induced DNA damage in IGF-1R-negative cells caused G(1) cell cycle arrest and S phase fork stalling. Taken together, our results suggest a role of IGF-1R in DDT.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/626186 |
| Date | 03 November 2017 |
| Creators | Waraky, Ahmed, Lin, Yingbo, Warsito, Dudi, Haglund, Felix, Aleem, Eiman, Larsson, Olle |
| Contributors | Univ Arizona, Phoenix Childrens Hosp, Inst Mol Med, Univ Arizona, Coll Med, Dept Child Hlth |
| Publisher | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2017 by The American Society for Biochemistry and Molecular Biology, Inc. |
| Relation | http://www.jbc.org/lookup/doi/10.1074/jbc.M117.781492 |
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