Biochemical characterization of the feedforward loop between CDK1 and FOXM1 in epidermal stem cells

Biol Direct. 2024 Oct 13;19(1):91. doi: 10.1186/s13062-024-00540-8.

Abstract

The complex network governing self-renewal in epidermal stem cells (EPSCs) is only partially defined. FOXM1 is one of the main players in this network, but the upstream signals regulating its activity remain to be elucidated. In this study, we identify cyclin-dependent kinase 1 (CDK1) as the principal kinase controlling FOXM1 activity in human primary keratinocytes. Mass spectrometry identified CDK1 as a key hub in a stem cell-associated protein network, showing its upregulation and interaction with essential self renewal-related markers. CDK1 phosphorylates FOXM1 at specific residues, stabilizing the protein and enhancing its nuclear localization and transcriptional activity, promoting self-renewal. Additionally, FOXM1 binds to the CDK1 promoter, inducing its expression.We identify the CDK1-FOXM1 feedforward loop as a critical axis sustaining EPSCs during in vitro cultivation. Understanding the upstream regulators of FOXM1 activity offers new insights into the biochemical mechanisms underlying self-renewal and differentiation in human primary keratinocytes.

Keywords: CDK1; Epidermal stem cell; FOXM1; Phosphorylation.

MeSH terms

  • CDC2 Protein Kinase* / genetics
  • CDC2 Protein Kinase* / metabolism
  • Cell Differentiation
  • Cells, Cultured
  • Epidermal Cells* / metabolism
  • Epidermis / metabolism
  • Forkhead Box Protein M1* / genetics
  • Forkhead Box Protein M1* / metabolism
  • Humans
  • Keratinocytes* / cytology
  • Keratinocytes* / metabolism
  • Phosphorylation
  • Stem Cells* / cytology
  • Stem Cells* / metabolism

Substances

  • Forkhead Box Protein M1
  • FOXM1 protein, human
  • CDC2 Protein Kinase
  • CDK1 protein, human