{"entity": "publication", "iuid": "398fef6d98d2430f9428b122615fe54f", "timestamp": "2026-09-06T11:03:18.932Z", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/398fef6d98d2430f9428b122615fe54f.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/398fef6d98d2430f9428b122615fe54f"}}, "title": "Comparison of CX-4945 and SGC-CK2-1 as inhibitors of CSNK2 using quantitative phosphoproteomics: Triple SILAC in combination with inhibitor-resistant CSNK2.", "authors": [{"family": "Menyhart", "given": "Daniel", "initials": "D"}, {"family": "Gyenis", "given": "Laszlo", "initials": "L"}, {"family": "Jurcic", "given": "Kristina", "initials": "K"}, {"family": "Roffey", "given": "Scott E", "initials": "SE"}, {"family": "Puri", "given": "Aakshi", "initials": "A"}, {"family": "Jovanovic", "given": "Predrag", "initials": "P"}, {"family": "Szkop", "given": "Krzysztof J", "initials": "KJ"}, {"family": "Pittock", "given": "Paula", "initials": "P"}, {"family": "Lajoie", "given": "Gilles", "initials": "G"}, {"family": "Axtman", "given": "Alison D", "initials": "AD"}, {"family": "Larsson", "given": "Ola", "initials": "O"}, {"family": "Topisirovic", "given": "Ivan", "initials": "I"}, {"family": "Litchfield", "given": "David W", "initials": "DW"}], "type": "journal article", "published": "2023-05-01", "journal": {"title": "Curr Res Chem Biol", "issn": "2666-2469", "volume": "3", "issn-l": null}, "abstract": "Specificity is a limiting factor when using small-molecule inhibitors to study protein kinase signalling. Since inhibitor-resistant kinase mutants (i.e., drug-resistant alleles) remain active in the presence of inhibitor, they facilitate validation of on-target effects. By combining an inhibitor-resistant kinase mutant with mass spectrometry-based phosphoproteomics, we previously devised a systematic strategy for reliable identification and validation of CSNK2 substrates. In this study, we use the same strategy to evaluate the selectivity of CX-4945, a clinical stage CSNK2 inhibitor, and SGC-CK2-1, a chemical probe selectively targeting CSNK2. Human osteosarcoma (U2OS) cells expressing exogenous wild-type CSNK2A1 (WT) or an inhibitor-resistant triple mutant (TM, V66A/H160D/I174A) were treated with CX-4945 or SGC-CK2-1 prior to analysis using triple SILAC (phospho) proteomics. The minority of phosphosites, 15% at 4 h and 5% at 24 h, that were significantly downregulated in response to CX-4945 treatment were determined to be CSNK2A1-dependent. By comparison, the majority of phosphosites, >55% at both 4 and 24 h, that were significantly downregulated in response to SGC-CK2-1 were identified as CSNK2A1-dependent. This indicates that SGC-CK2-1 exhibits significantly greater selectivity towards CSNK2A1 than CX-4945. Notably, utilization of SGC-CK2-1 in cells expressing CSNK2A1-TM enabled the identification of >300 CSNK2A1-dependent phosphosites. Overall, this study highlights the utility of exploiting highly selective chemical probes together with inhibitor-resistant kinase mutants to facilitate identification of bona fide kinase substrates.", "doi": "10.1016/j.crchbi.2023.100041", "pmid": "41883516", "labels": [], "xrefs": [{"db": "mid", "key": "NIHMS1948074"}, {"db": "pmc", "key": "PMC13012654"}, {"db": "pii", "key": "100041"}], "notes": [], "created": "2026-08-20T07:53:11.110Z", "modified": "2026-08-20T07:53:11.177Z"}