Dynamic changes to survivin subcellular localization are initiated by DNA damage

Maritess Gay Asumen¹, Tochukwu V Ifeacho², Luke Cockerham³, Christina Pfandl⁴, Nathan R Wall<sup>3

1</sup>Touro University’s College of Osteopathic Medicine, Vallejo, CA, USA; ²University of Southern California, Los Angeles, CA, USA; ³Center for Health Disparities Research and Molecular Medicine, Loma Linda University, CA, USA; ⁴Green Mountain Antibodies, Burlington, VT, USA

Abstract: Subcellular distribution of the apoptosis inhibitor survivin and its ability to relocalize as a result of cell cycle phase or therapeutic insult has led to the hypothesis that these subcellular pools may coincide with different survivin functions. The PIK kinases (ATM, ATR and DNA-PK) phosphorylate a variety of effector substrates that propagate DNA damage signals, resulting in various biological outputs. Here we demonstrate that subcellular repartitioning of survivin in MCF-7 cells as a result of UV light-mediated DNA damage is dependent upon DNA damage-sensing proteins as treatment with the pan PIK kinase inhibitor wortmannin repartitioned survivin in the mitochondria and diminished it from the cytosol and nucleus. Mitochondrial redistribution of survivin, such as was recorded after wortmannin treatment, occurred in cells lacking any one of the three DNA damage sensing protein kinases: DNA-PK, ATM or ATR. However, failed survivin redistribution from the mitochondria in response to low-dose UV occurred only in the cells lacking ATM, implying that ATM may be the primary kinase involved in this process. Taken together, this data implicates survivian’s subcellular distribution is a dynamic physiological process that appears responsive to UV light- initiated DNA damage and that its distribution may be responsible for its multifunctionality.

Keywords: survivin, PIK kinases, ATM, ATR, DNA-PK