While the proper selection of splice sites drives genomic diversity, adaptive growth and development, errors in splicing can have enormous detrimental effects on function and is now recognized as the underlying cause for many human diseases. Indeed, splicing errors are associated with muscular dystrophy, Alzheimer's disease, Parkinsonism, psychiatric disorders, ataxias and cancers making the study of factors that control splice-site selection vitally important for human health. Splicing occurs at the spliceosome, a macromolecular complex composed of several RNAs and numerous proteins. Critical to normal gene splicing is the proper selection of the 5'-3' splice sites, events that occur early in the development of the spliceosome and whose specificity is guided by an essential family of splicing factors known as SR proteins. The phosphorylation states of SR proteins directly impact their subcellular localization and splicing activities but our understanding of how these different forms are attained is, at best, incomplete. The CLK family of protein kinases phosphorylates SR proteins and mobilizes them to sites of active gene splicing. The CLKs differ from many classic protein kinases in that they lack a docking groove for substrate binding but instead contain a disordered N-terminal extension that we showed attaches to the SR protein. In this proposal we will explore the role of the N-terminus for the mobilization of CLK1 and recognition of SR proteins in the nucleus using a wide array of in vivo and in vitro experiments. We will study the effects of CLK-dependent phosphorylation on SR protein conformation, subcellular localization, and interactions with critical mediators of splice-site selection in the spliceosome. The larger goal of this proposal is to define CLK function at both biological and biochemical levels so that we can better understand the mechanisms of human diseases associated with errors in splicing.
Although many human diseases have their origins in the mis-splicing of genes, we still do not understand the fundamental mechanism controlling the selection of splice sites. The phosphorylation of certain protein factors has been linked to changes in splicing but the mechanism underlying these changes are not well known. To understand the connection between phosphorylation, splicing and disease we are studying the structure and biological function of the CLK family of protein kinases, an enzyme family that phosphorylates these splicing factors and modifies gene splicing.
| Aubol, Brandon E; Serrano, Pedro; Fattet, Laurent et al. (2018) Molecular interactions connecting the function of the serine-arginine-rich protein SRSF1 to protein phosphatase 1. J Biol Chem 293:16751-16760 |
| Aubol, Brandon E; Keshwani, Malik M; Fattet, Laurent et al. (2018) Mobilization of a splicing factor through a nuclear kinase-kinase complex. Biochem J 475:677-690 |
| Aubol, Brandon E; Hailey, Kendra L; Fattet, Laurent et al. (2017) Redirecting SR Protein Nuclear Trafficking through an Allosteric Platform. J Mol Biol 429:2178-2191 |
| Keshwani, Malik M; Aubol, Brandon E; Fattet, Laurent et al. (2015) Conserved proline-directed phosphorylation regulates SR protein conformation and splicing function. Biochem J 466:311-22 |
| Barkho, Sulyman; Pierce, Levi C T; Li, Sheng et al. (2015) Theoretical Insights Reveal Novel Motions in Csk's SH3 Domain That Control Kinase Activation. PLoS One 10:e0127724 |
| Keshwani, Malik M; Hailey, Kendra L; Aubol, Brandon E et al. (2015) Nuclear protein kinase CLK1 uses a non-traditional docking mechanism to select physiological substrates. Biochem J 472:329-38 |
| Aubol, Brandon E; Plocinik, Ryan M; Keshwani, Malik M et al. (2014) N-terminus of the protein kinase CLK1 induces SR protein hyperphosphorylation. Biochem J 462:143-52 |
| Aubol, Brandon E; Plocinik, Ryan M; Hagopian, Jonathan C et al. (2013) Partitioning RS domain phosphorylation in an SR protein through the CLK and SRPK protein kinases. J Mol Biol 425:2894-909 |
| Aubol, Brandon E; Jamros, Michael A; McGlone, Maria L et al. (2013) Splicing kinase SRPK1 conforms to the landscape of its SR protein substrate. Biochemistry 52:7595-605 |
| Aubol, Brandon E; Plocinik, Ryan M; McGlone, Maria L et al. (2012) Nucleotide release sequences in the protein kinase SRPK1 accelerate substrate phosphorylation. Biochemistry 51:6584-94 |
