| Our previous study shows that candidate tumor suppressor MARVELD1 was downregulated in multiple primary tumors. Phylogenetic analysis demonstrates that mouse mP19 is 88% conserved to its human counterpart MARVELD1 with highly consensus domains. Therefore, in this study, we prefer to elucidate the cellular function of mP19 by means of the biochemical and cytology methods to assess the similarities and differences between mP19 and MARVELD1, which may provide important insights into the foundation of mP19-transgenic mouse.Bioinformatics analysis shows that mp19 and its homologs exist in the genomes of vertebrates and highly conserved in various mammalian species. By BLAST searching, four candidate PKC phosphorylation sites (Thr15, Ser19, Thr51, Thr120) were predicted to locate in mP19, while only one (Thr51) in human MARVELD1. According to the clues, we identified the Thr phosphorylation site of mP19 using immunoprecipitation and western blot analysis and considered that Thr51 could be the direct phosphorylation site by PKC according to its high identity between mP19 and human MARVELD1. Further immunofluorescence analysis shows that mP19 exhibits a cell cycle-dependent cellular localization. It was observed to be in the nucleus and at the perinuclear region at interphase, while with the clear mitotic spindle and the midbody during mitosis.In addition, our study suggests that mP19 translocates into the nucleus induced by PMA, a PKC activator. By co-immunoprecipitation assay,α-tubulin was identified to be the interacted protein of mP19. Moreover, treatment of cells with colchicine, a microtubule-depolymerizing agent, translocation of the whole fraction of mMARVELD1 was observed. We also found that overexpressed mP19 affected the assembly of microfilament, cellular surface micro-structure and stress fiber. Finally, overexpression of mMARVELD1 in NIH3T3 cells resulted in a remarkable inhibition of cell proliferation, G1-phase arrest, and reduced cell migration.
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