[Expression and function of VAP-33 in murine dendritic cell sarcoma]

To elucidate the expression and function of VAP-33 gene in dendritic cell sarcoma (DCS) cell line.

The expression of VAP-33 in DCS cells was investigated by mass spectrum with immunoprecipitation membrane protein. DCS cells were treated with antigens in different dosages (150, 850, and 1500 microl) for 24, 48 and 72 h respectively. Cell morphology and phagocytosis activity of DCS cells were measured. Indirect immunofluorescence, confocal microscopy and Western blotting were used to study the distribution and expression changes of VAP-33. Moreover, DCS cells were treated with 0.5 mol/L insulin for 20 min first and followed by Western blotting to detect changes of VAP-33 and glucose transfer protein 4 (GLUT-4) in the total cellular protein, cytoplasmic protein and membrane protein. Confocal microscopy was used to document the expression and distribution changes of VAP-33 and GLUT-4 in DCS cells.

VAP-33 expression was obtained at the cell membrane and in the cytoplasm of DCS cells. Upon antigen stimulation, DCS cells showed more active phagocytosis and morphologically became more elongated with branched protrusions. The expression of VAP-33 was decreased by the antigen stimulation. Upon the insulin stimulation, the expression of VAP-33 and GLUT-4 were increased and co-localized.

VAP-33 expression in DCS originated from the dendritic cells (DC) seemed relating to the vesicle transportation during antigen processing in DC. Additionally, VAP-33 and GLUT-4 also take part in the glucose transportation in the cells.