Phosphorylation of H2AX is believed to be associated with the repair of damaged DNA. Recent findings suggest a novel function of H2AX in cellular apoptosis. Specifically, it was shown that ultraviolet A-activated JNK phosphorylates H2AX to regulate apoptosis. Here we show that serum starvation induces H2AX phosphorylation and apoptosis independent of the JNK pathway. Serum starvation induced p38 phosphorylation, whereas it did not affect the phosphorylation of ERK or JNK. Inhibition of p38 reduced H2AX phosphorylation and apoptosis. Furthermore, p38 was found to phosphorylate H2AX directly in vitro and was colocalized with H2AX in vivo. Finally, we demonstrate that H2AX phosphorylation is required for serum starvation-induced apoptosis. Taken together, these data elucidate a novel signaling pathway (p38/H2AX) to regulate apoptosis.

ABSTRACT. We detected autoantibodies against melanocytes in serum samples obtained from 50 patients, including 4 with HBV, with vitiligo and identified the associated membrane antigens. Heat shock protein 70 (HSP70) and anti-tyrosinase-related protein 1 (TRP-1) antibody levels were analyzed. The associated antigens in normal human melanocyte were identified by immunofluorescence. Autoantibodies against melanocyte membrane and cytoplasmic proteins were detected by western blot. Membrane antigens with higher frequencies were identified by protein mass spectrometry. The HSP70 and anti-TRP-1 antibody levels (N = 70; 10 with HBV) were detected by ELISA. The specific antigens were detected in melanocyte cytoplasm and membrane (40/50; 80% incidence; western blot). The autoantibodies reacted with several membrane antigens with approximate molecular weights (Mr) of 86

ABSTRACT. We investigated the effects of simulated weightlessness on cellular morphology, proliferation, cell cycle, and apoptosis of the human gastric carcinoma cell line SGC-7901 and the human gastric normal cell line HFE-145. A rotating clinostat was used to simulate weightlessness. The Image-Pro4.5 image analysis system was used for morphometric analysis. Proliferating cell nuclear antigen expression was examined by immunohistochemical staining. Changes in the cell cycle were examined using a cytometer. Apoptosis was measured using the terminal dUTP nick-end labeling (TUNEL) method. When subjected to simulated weightlessness, the cellular morphology of SGC-7901 cells was changed at 12, 24, 48, and 72 h, cell conversion from the G 1 to S phase was blocked, proliferation was inhibited at 48 and 72 h, and the apoptosis index was increased at 72 h. The same changes were observed for HFE-145 cells at 12 h when subjected to simulated weightlessness, but no significant changes were found 6061 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 13 (3): 6060-6069 (2014) Effects of simulated weightlessness on cellular morphology afterward compared with controls. SGC-7901 cells change their cellular morphology and biological characteristics during clinostat-simulated weightlessness at 72 h, but HFE-145 cells only change at 12 h and adapt to simulated weightlessness after that point.

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