Effect of SRPK1 depletion or inhibition of its kinase activity on endogenous Rac1b and SRSF1 levels. (A) Western blot analysis of SRPK1, Rac1b, and SRSF1 protein levels in HT29 cells following transfection with SRPK1-specific siRNAs for 48 h. Levels of phosphorylated SRSF1 were also detected. (B) Quantitative PCR analysis of endogenous Rac1b and SRSF1 transcript levels in HT29 cells following transfection with either SRPK1-specific or, for comparison, GSK3β-specific siRNAs. (C) Inhibition of SRPK1 activity in HT29 cells by incubation with 25 μM SRPIN340 or control components during 24 h. Shown is a Western blot analysis of the endogenous levels of Rac1b and SRSF1 protein as well as of SRSF1 phosphorylation.
