Abstract
Backgroud: Abnormal aging processes are critical in the pathogenesis of chronic lung diseases. We demonstrated that A549 cells with decreased expression of Protein L-isoaspartate (D-Aspartate) O-methyltransferase (PCMT1) increased accumulation of D-Aspartate residues in Prohibitin1 (PHB1) expressed in mitochondria, nucleus and plasma membrane [1]. This process is initiated by the asparagine (Asn) residue deamidation. Recent study showed that interplays between lipid droplets and mitochondria are associated with aging and that furthermore, PHB1 in the nucleus is involved in cell proliferation. The aim of this study consists of two issues to address the effects on lipid droplet size and cell proliferation in alveolar epithelial cell line, A549 cells.
Methods: Based on the propensity of deamidation of Asn residue adjacent to C-terminal Gly or Ser residues, mutant prohibitin (N24D and N226D) was transfected to A549 cells. Lipid droplet sizes were evaluated by oil red O staining. Cell proliferation was analyzed by wound healing assays.
Results: A549 cells expressing mutant Prohibitins revealed the significantly larger size of lipid droplets. Furthermore A549 cells expressing N24D mutant Prohibitin showed significantly decreased cell proliferation.
Conclusion: Deamidation of Asn residues is involved in larger lipid droplet formation and cell proliferation.
Key words: deamidation, prohibitin, aging
This work was supported by Grant in-Aid from the ministry of Education, Culture, Sports Science, and Technology of Japan (26461194 and 22590842)(K.Y.) and (20590925)(M.O.).
Reference:
1. Ogasawara M et al. Exp Lung Res 2016; 42(5):245-62.
