Figure 1.

Localization of SRPK1 in interphase HeLa cells. Endogenous SRPK1 and SC35 were localized using a mouse monoclonal anti-SRPK1 and rabbit polyclonal anti-SC35 antibodies (A and B). SRPK1 is mainly present in the cytoplasm with a fraction clearly detectable in the nucleus. Some colocalization of SRPK1 with SC35 in nuclear speckles is evident under a standard inverted fluorescence microscope (C). Confocal microscopy confirmed the localization of SRPK1 in both the cytoplasm and the nucleus (D). SRPK1 and SC35 are diffused in the nucleus at a single focal level (E and F). No staining was detected in the absence of primary antibodies (G, red channels; H, green channels). Nuclei were stained with DAPI (I).