Fig. 6

Fig. 6 SRPK3 phosphorylates RBM20 in vitro.

a, The RBM20_517–664-V5 reporter was transfected into 293T cells with or without GFP-SRPK3. GFP-SRPK3/RBM20_517–664-V5 co-expression resulted in RBM20_517–664-V5 hyperphosphorylation (lanes 4 and 5), as indicated by a mobility shift that was abolished by incubation with lambda phosphatase (P, lane 6). U indicates untreated samples; N indicates control samples incubated without phosphatase. In the absence of the SRPK3 construct, a less pronounced but still noticeable mobility shift can be observed (lanes 1 and 2), consistent with RBM20 phosphorylation by endogenous kinases such as SRPK1, CLK1 or AKT2. Assay was performed in quadruplicate. b, mRNA counts of the zebrafish RBM20 ortholog (BX649294.1 ENSDARG00000092881) are increased in srpk3-null zebrafish (srpk3^−/−; ttn.1^+/+ and srpk3^−/−; ttn.1^+/−), likely as a feedback loop due to the srpk3 deficiency. The box blots represent the first and third quartiles (25% and 75% percentile) with the center line at the median value. The whiskers extend from the hinge to the furthest value not beyond 1.5 times the interquartile range from the hinge. Differential expression was done using a two-sided Wald test with Benjamini–Hochberg adjustment for multiple testing⁶³. For srpk3^−/−; ttn.1^+/+ versus srpk3^+/+; ttn.1^+/+, *P = 0.0379. n = 6 for each condition. Full-length blots are provided as source data.

Source data