PI3Kβ functions as a protein kinase to promote cellular protein O-GlcNAcylation and acetyl-CoA production for tumor growth

Mol Cell. 2025 Apr 3;85(7):1411-1425.e8. doi: 10.1016/j.molcel.2025.02.024. Epub 2025 Mar 24.

Abstract

Phosphatidylinositol 3-kinase (PI3K) phosphorylates PI(4,5)P2 to produce PI(3,4,5)P3, thereby activating AKT and other effector proteins. However, whether PI3K has non-PI(3,4,5)P3-related functions critical for tumor development remains unclear. Here, we demonstrate that high glucose induces PI3Kβ binding to O-linked β-D-N-acetylglucosamine (O-GlcNAc) transferase (OGT) in glioblastoma cells, dependent on hexokinase 1 (HK1)-mediated OGT Y889 phosphorylation and subsequent p85α recruitment. Importantly, PI3Kβ functions as a protein kinase, phosphorylating OGT at T985 and enhancing OGT activity and total cellular protein O-GlcNAcylation. Activated OGT O-GlcNAcylates ATP-citrate synthase (ACLY) at T639 and S667, leading to ACLY activation-dependent acetyl-coenzyme A (CoA) production to increase fatty acid levels and histone H3 acetylation for gene transcription. Intervention in PI3Kβ-mediated OGT phosphorylation and ACLY O-GlcNAcylation inhibits glioblastoma cell proliferation and tumor growth in xenografts. These findings underscore the critical role of PI3Kβ in governing protein O-GlcNAcylation, fatty acid metabolism, and chromatin modification through its protein kinase activity and provide instrumental insight into the roles of PI3K in tumor progression.

Keywords: ACLY; HK1; OGT; PI3K; acetyl-CoA; fatty acid production; histone; tumor.

MeSH terms

  • Acetyl Coenzyme A* / biosynthesis
  • Acetyl Coenzyme A* / metabolism
  • Acetylation
  • Animals
  • Cell Line, Tumor
  • Cell Proliferation
  • Glioblastoma* / enzymology
  • Glioblastoma* / genetics
  • Glioblastoma* / metabolism
  • Glioblastoma* / pathology
  • Glucose / metabolism
  • Histones / metabolism
  • Humans
  • Mice
  • Mice, Nude
  • N-Acetylglucosaminyltransferases* / genetics
  • N-Acetylglucosaminyltransferases* / metabolism
  • Phosphorylation

Substances

  • N-Acetylglucosaminyltransferases
  • Acetyl Coenzyme A
  • OGT protein, human
  • Glucose
  • Histones