Nuclear speckles are membraneless organelles that act as active splicing hubs especially at sites of high transcription; emerging views of this dynamic subnuclear structure place it as a hub of RNA processing from transcription to export. To manage a complex microcosm of RNA metabolism, nuclear speckles also require phosphorylation and kinases to execute their functions. We identified a nuclear speckle-localized kinase, TAOK2, as able to mediate the splicing and export of a transcript at the nuclear speckle. To characterize its cellular regulatory capacity at the endogenous nuclear speckle, we used siRNA knockdown of both whole cell and nucleocytoplasmic fractions to characterize the complete endogenous effects of TAOK2. We found that TAOK2 knockdown can impact over 10% of the transcriptome. Cellular and biochemical phosphoproteomics reveals TAOK2 at the center of a nuclear speckle regulatory environment and identifies nuclear speckle scaffolding proteins SRRM1 and SRRM2 as potential direct phosphorylation targets mediating its large effects on the speckle. Indeed, knockdown of TAOK2 perturbs almost all serine/arginine (SR)-rich proteins while leaving heterogeneous ribonucleoproteins (HNRNPs) unperturbed. Altogether, we propose a structural maintenance role for phosphorylation by TAOK2 at SRRM1/2 that impacts SR protein-driven exon inclusion localized at the nuclear speckle.