Fig. 4

Curcumin increases the hyperphosphorylated isoform of SRSF1 in the nucleus. a Left panel Western blotting analysis of the fractionation of cytosol and nuclei of the BJ301J cells, GAPDH and hnRNP H/F are as the specific markers for cytosolic and nuclear fractions, respectively. Right panel Western blotting analysis of the expression of SRSF1 in total lysates (T), cytosolic (C) and nuclear (N) fractions of the BJ301J cells upon 24-h treatment with DMSO or 25 μM of curcumin. hnRNP H/F protein loading control. Two bands are shown in all of the lysate samples, both of them can be recognized by SRSF1 antibody (clone 96). b Western blotting analysis of SRSF1 protein isoforms in total lysates supplemented with different concentrations of NaF. The lower band of SRSF1 upon curcumin treatment is relatively much weaker than that in DMSO-treated cell lysate and not detected when a higher concentration of NaF (10 mM) was used. β-ACTIN protein loading control. c Western blot analysis of IP cytoplasmic SRSF1 protein in curcumin-treated BJ301J fibroblast cells with or without CIAP treatment. Black-filled and unfilled triangles indicate the hyperphosphorylated and the dephosphorylated isoforms of SRSF1, respectively. *Non-specific bands