Photo of Xiao-Xin Sun

Xiao-Xin Sun

    • Assistant Professor of Molecular and Medical Genetics School of Medicine

During her PhD study at OHSU, Dr. Sun focused on molecular and biochemical mechanisms underlying the regulation of p53-MDM2 pathway. Particularly, she has discovered that aberrant expression of the nucleolar protein nucleostemin activates p53 signaling. She also identified that several chemotherapieutic agents induce p53 by triggering ribosomal stress. After graduation, Dr. Sun joined the Riley Heart Research Center at Indiana University School of Medicine to investigate the function of Phosphatase of regenerating liver family proteins (PRL1, PRL2, and PRL3) in animal development and relevant human diseases, including cancer, using knockout mice models. She received a postdoctoral fellowship from the Cancer Biology Training Program at Indiana University during this period. In 2009, Dr. Sun returned to OHSU and joined Mushui's lab. She is now continuing on the characterization of the regulation of p53-MDM2 pathway.


  • "The nucleolar ubiquitin-specific protease USP36 deubiquitinates and stabilizes c-Myc" Proceedings of the National Academy of Sciences of the United States of America March 24 2015
  • "Ribosomal protein L11 recruits miR-24/miRISC to repress c-Myc expression in response to ribosomal stress" Molecular and Cellular Biology October 2011
  • "Ribosomal protein L23 activates p53 by inhibiting MDM2 function in response to ribosomal perturbation but not to translation inhibition" Molecular and Cellular Biology September 2004
  • "Inhibition of c-Myc activity by ribosomal protein L11" EMBO Journal July 25 2007
  • "Physical and functional interaction between ribosomal protein L11 and the tumor suppressor ARF" Journal of Biological Chemistry May 18 2012
  • "Mycophenolic acid activation of p53 requires ribosomal proteins L5 and L11" Journal of Biological Chemistry May 2 2008
  • "Identification and characterization of nuclear and nucleolar localization signals in the adeno-associated virus serotype 2 assembly-activating protein" Journal of Virology  2015
  • "Positive regulation of p53 stability and activity by the deubiquitinating enzyme Otubain 1" EMBO Journal February 1 2012
  • "Perturbation of 60 S ribosomal biogenesis results in ribosomal protein L5- and L11-dependent p53 activation" Journal of Biological Chemistry August 13 2010
  • "Monoubiquitination is critical for ovarian tumor domain-containing ubiquitin aldehyde binding protein 1 (Otub1) to suppress UbcH5 enzyme and Stabilize p53 protein" Journal of Biological Chemistry February 21 2014
  • "Aberrant expression of nucleostemin activates p53 and induces cell cycle arrest via inhibition of MDM2" Molecular and Cellular Biology July 2008
  • "Ribosomal protein L11 associates with c-Myc at 5 S rRNA and tRNA genes and regulates their expression (Journal of Biological Chemistry (2005) 280, (12587-12594))" Journal of Biological Chemistry December 10 2010
  • "5-fluorouracil activation of p53 involves an MDM2-ribosomal protein interaction" Journal of Biological Chemistry March 16 2007
  • "Erratum" EMBO Journal April 8 2009
  • "Interplay between ribosomal protein S27a and MDM2 protein in p53 activation in response to ribosomal stress" Journal of Biological Chemistry July 1 2011
  • "Nucleostemin stabilizes ARF by inhibiting the ubiquitin ligase ULF" Oncogene April 28 2014
  • "Ribosomal protein L11 associates with c-Myc at 5 S rRNA and tRNA genes and regulates their expression" Journal of Biological Chemistry April 23 2010
  • "Ubiquitin- and MDM2 E3 ligase-independent proteasomal turnover of nucleostemin in response to GTP depletion" Journal of Biological Chemistry March 23 2012
  • "Identification and characterization of a novel Drosophila melanogaster glutathione S-transferase-containing FLYWCH zinc finger protein" Gene November 1 2004
  • "Regulation of the MDM2-p53 pathway by ribosomal protein L11 involves a post-ubiquitination mechanism" Journal of Biological Chemistry August 25 2006
  • "MicroRNA-130a associates with ribosomal protein L11 to suppress c-Myc expression in response to UV irradiation" Oncotarget  2015
  • "MDMX promotes proteasomal turnover of p21 at G1 and early S phases independently of, but in cooperation with, MDM2" Molecular and Cellular Biology February 2008
  • "Deubiquitinating c-Myc" Cell Cycle January 1 2015
  • "Ribosomal protein L4 is a novel regulator of the MDM2-p53 loop" Oncotarget March 29 2016
  • "Phosphatase of regenerating liver 2 (PRL2) is essential for placental development by down-regulating PTEN (phosphatase and tensin homologue deleted on chromosome 10) and activating Akt protein" Journal of Biological Chemistry September 14 2012
  • "Fkbp1a controls ventricular myocardium trabeculation and compaction by regulating endocardial Notch1 activity" Development (Cambridge) May 1 2013
  • "Otub1 stabilizes MDMX and promotes its proapoptotic function at the mitochondria" Oncotarget  2017
  • "p73 to the rescue" Oncotarget  2017
  • "RHEB1 insufficiency in aged male mice is associated with stress-induced seizures" GeroScience September 10 2017
  • "microRNA-130a suppresses breast cancer cell migration and invasion by targeting FOSL1 and upregulating ZO-1" Journal of Cellular Biochemistry January 1 2018

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