Updated project metadata. We found that RPL22L1 isoform switch is regulated by SRSF4 protein and identified a small molecule compound FG1059, that inhibits this process and decreases tumor growth. To confirm that FG1059 affects RPL22L1 due to the inhibition of SRSF protein phosphorylation we studied the phosphoproteome of patient-derived GBM neurospheres treated with FG1059 for 0, 3, 6 and 12 hours.