Continuous increase in phosphorylation of cytosolic thymidine kinase during proliferation of rat hepatoma JB1 cells.

摘要: Thymidine kinase (TK) is a protein closely associated with DNA replication. Here we show that, in contrast the variation of TK activity, which changed parallel S phase cell distribution during asynchronous culture rat hepatoma JB1 cells, serine residues cytosolic was phosphorylated continuously response to increasing G0/G1 distribution. The shifting phosphorylation different growth conditions further confirmed examination elution profile activity by anion-exchange high performance liquid chromatography (HPLC). HPLC analysis revealed that rapid proliferating (62 h after culture) JB 1 cells showed only hyperphosphorylated form while synchronously M phase-arrested hypo- and hyper-phosphorylated forms activity. These results suggested modulation cycle-dependent, might be involved negative regulation vivo.