Mutually exclusive acetylation and ubiquitylation of the splicing factor SRSF5 control tumor growth

Abstract

Most tumor cells take up more glucose than normal cells. Splicing dysregulation is one of the molecular hallmarks of cancer. However, the role of splicing factor in glucose metabolism and tumor development remains poorly defined. Here, we show that upon glucose intake, the splicing factor SRSF5 is specifically induced through Tip60-mediated acetylation on K125, which antagonizes Smurf1-mediated ubiquitylation. SRSF5 promotes the alternative splicing of CCAR1 to produce CCAR1S proteins, which promote tumor growth by enhancing glucose consumption and acetyl-CoA production. Conversely, upon glucose starvation, SRSF5 is deacetylated by HDAC1, and ubiquitylated by Smurf1 on the same lysine, resulting in proteasomal degradation of SRSF5. The CCAR1L proteins accumulate to promote apoptosis. Importantly, SRSF5 is hyperacetylated and upregulated in human lung cancers, which correlates with increased CCAR1S expression and tumor progression. Thus, SRSF5 responds to high glucose to promote cancer development, and SRSF5-CCAR1 axis may be valuable targets for cancer therapeutics.