FIG. 2.

Cellular localization of SHMT in T. vaginalis transfectants. (A) Cells expressing HA-tagged SHMT were stained for immunofluorescence microscopy using a mouse HA-tagged antibody. T. vaginalis anti-Hsp70 was used as a positive control for hydrogenosomal localization (10). The nucleus (blue) was stained with 4′,6′-diamidino-2-phenylindole (DAPI), SHMT was stained with mouse anti-HA (green), and Hsp70 was stained with rabbit anti-Hsp70 (red). Merged images demonstrate the colocalization of SHMT and Hsp70. PC indicates the phase-contrast image. (B) SHMT activity using variable amounts of hydrogenosomal and cytosolic extracts prepared using untransfected T. vaginalis cells in the presence of 2 mM THF and 0.25 mM externally added PLP. Enzyme activity was expressed as pmol of methylenetetrahydrofolate formed per min per mg of total protein. Solid bars (A) represent activity in hydrogenosomal extracts; open bars (B) represent activity in cytosolic extracts. Error bars reflect standard deviations of results from three measurements.