Identification of RSK substrates using an analog-sensitive kinase approach

ABSTRACT: RSK1 and RSK4 are two of the four members of the p90 ribosomal protein S6 kinases (RSK) family. These kinases are downstream kinases of mitogen-activated protein kinase 1 (ERK or MAPK1) in the ERK MAP kinase pathway. RSKs are implicated in fine tuning of cellular processes such as translation, transcription, proliferation, and motility. Previous work showed that pathogens such as Cardioviruses could hijack any of the four RSK isoforms to inhibit PKR activation or to disrupt cellular nucleocytoplasmic trafficking. In contrast, some reports suggest non-redundant functions for distinct RSK isoforms and Coffin-Lowry syndrome has only been associated with mutations in the gene encoding RSK2. In this work, we used the analog-sensitive kinase strategy to ask whether the cellular substrates of distinct RSK isoforms differ. We therefore compared the substrates of 2 of the most distant RSK isoforms: RSK1 and RSK4. We identified a series of potential substrates for both RSKs in cells, and validated RanBP3, PDCD4, IRS2 and ZC3H11A as substrates of both RSK1 and RSK4, and SORBS2 as a RSK1 substrate. In addition, using mutagenesis and inhibitors, we confirmed analog-sensitive kinase data showing that endogenous RSKs phosphorylate TRIM33 at S1119. Our data thus identify a series of potential RSK substrates and suggest that the substrates of RSK1 and RSK4 largely overlap and that the specificity of the various RSK isoforms likely depends on their cell- or tissue-specific expression pattern.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Didier Vertommen  

LAB HEAD: Thomas Michiels

PROVIDER: PXD047020 | Pride | 2024-02-06

REPOSITORIES: Pride