Fig. 4: The acetylation of SNRNP200 at lysine 1610 safeguards it from proteasomal degradation. | Cell Discovery

Fig. 4: The acetylation of SNRNP200 at lysine 1610 safeguards it from proteasomal degradation.

From: Targeting SNRNP200-induced splicing dysregulation offers an immunotherapy opportunity for glycolytic triple-negative breast cancer

Fig. 4

a Endogenous SNRNP200 was immunoprecipitated from HEK293T cells and analyzed by LC-MS. The data show MS2 spectra for a signature peptide acetylated at K1610. b Alignment of the SNRNP200 protein sequence across different species. c A secondary structure model of SNRNP200 was visualized via SWISS-MODEL68. The K1610 residue is highlighted with a different color. d HEK293T cells were transfected with Myc-tagged SNRNP200 WT, K1610R, or K1610Q plasmids for 36 h with or without TSA. The acetylation levels of SNRNP200 were quantified against immunoprecipitated Myc-tag and are presented as the mean ± SEM. e HEK293T cells were transfected with the indicated plasmids and treated with glucose at either 2.5 mM or 25 mM. Ubiquitylation analysis was revealed by immunoblotting. f HDAC1, HDAC2, and HDAC5 were overexpressed in HEK293T cells treated with or without TSA. The acetylation levels of SNRNP200 were determined by immunoblotting. Co-IP assays were performed to determine the interaction between SNRNP200 and HDAC5. g HEK293T cells were maintained in a medium supplemented with either 2.5 mM or 25 mM glucose. The SNRNP200 ubiquitylation levels were determined via IP-western blotting. Co-IP assays were performed to determine the dynamic interactions between SNRNP200 and HDAC5. h BT-549 cells were transfected with siRNF123 or the control. The levels of ubiquitinated SNRNP200 were analyzed by immunoblotting. i, j BT-549 cells maintained in 2.5 mM glucose were transfected with siRNF123 or the control and treated with CHX as previously described. The endogenous SNRNP200, EFTUD2, and PRPF8 proteins were analyzed by immunoblotting (i) and quantified against actin (j). The data for the relative SNRNP200 levels are presented as the mean ± SEM. k Working model illustrating the mutually exclusive acetylation and ubiquitylation of SNRNP200 in glycolytic TNBCs. For d and j, the data were compared using Student’s t-test: ns not significant, P > 0.05; *P < 0.05; **P < 0.01.

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