UHMK1 is a novel splicing regulatory kinase

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Arfelli, Vanessa C. ; Chang, Yun-Chien ; Bagnoli, Johannes W. ; Kerbs, Paul ; Ciamponi, Felipe E. ; Paz, Laissa M. da S. ; Pankivskyi, Serhii ; Salone, Jean de Matha ; Maucuer, Alexandre ; Massirer, Katlin B. ; Enard, Wolfgang ; Kuster, Bernhard ; Greif, Philipp A. ; Archangelo, Leticia Froehlich

• Document type: Journal article
• Source: Journal of Biological Chemistry; v. 299, n. 4, p. 22-pg., 2023-03-17.

Abstract

The U2AF Homology Motif Kinase 1 (UHMK1) is the only kinase that contains the U2AF homology motif, a common protein interaction domain among splicing factors. Through this motif, UHMK1 interacts with the splicing factors SF1 and SF3B1, known to participate in the 30 splice site recognition during the early steps of spliceosome assembly. Although UHMK1 phos-phorylates these splicing factors in vitro, the involvement of UHMK1 in RNA processing has not previously been demon-strated. Here, we identify novel putative substrates of this kinase and evaluate UHMK1 contribution to overall gene expression and splicing, by integrating global phosphoproteomics, RNA-seq, and bioinformatics approaches. Upon UHMK1 mod-ulation, 163 unique phosphosites were differentially phosphor-ylated in 117 proteins, of which 106 are novel potential substrates of this kinase. Gene Ontology analysis showed enrichment of terms previously associated with UHMK1 function, such as mRNA splicing, cell cycle, cell division, and microtubule orga-nization. The majority of the annotated RNA-related proteins are components of the spliceosome but are also involved in several steps of gene expression. Comprehensive analysis of splicing showed that UHMK1 affected over 270 alternative splicing events. Moreover, splicing reporter assay further sup-ported UHMK1 function on splicing. Overall, RNA-seq data demonstrated that UHMK1 knockdown had a minor impact on transcript expression and pointed to UHMK1 function in epithelial-mesenchymal transition. Functional assays demon-strated that UHMK1 modulation affects proliferation, colony formation, and migration. Taken together, our data implicate UHMK1 as a splicing regulatory kinase, connecting protein regulation through phosphorylation and gene expression in key cellular processes. (AU)

• FAPESP's process: 22/08648-9 - The role of the splicing regulatory kinase UHMK1 in Melanoma and its relationship with the long non-coding RNA RMEL3
• Grantee: Leticia Fröhlich Archangelo
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/01458-3 - Defining the functional role of the splicing factor regulator (KIS) during leukemogenesis using a murine bone marrow transplantion model
• Grantee: Leticia Fröhlich Archangelo
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 20/02006-0 - Molecular and structural characterization of RNA binding proteins acting as potential disease targets in cancer and neurology
• Grantee: Katlin Brauer Massirer
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE