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Protein kinase C-delta associates with vimentin intermediate filaments in differentiated HL60 cells

P J Owen1, G D Johnson, J M Lord

  • 1Department of Immunology, Birmingham University Medical School, United Kingdom.

Experimental Cell Research
|June 15, 1996
PubMed

Insights

Protein kinase C (PKC)-delta localizes to intermediate filaments in differentiated HL60 cells. This enzyme phosphorylates vimentin, suggesting a role in cell shape and adhesion during differentiation.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Molecular Biology

Background:

  • Protein Kinase C (PKC) delta is involved in cellular signaling pathways.
  • HL60 cells are a human promyelocytic leukemia cell line commonly used to study differentiation into monocyte/macrophage lineages.
  • Understanding the subcellular localization and substrates of PKC-delta is crucial for elucidating its role in cellular processes.

Purpose of the Study:

  • To determine the subcellular localization of PKC-delta in differentiated HL60 cells.
  • To investigate the interaction of PKC-delta with intermediate filaments during differentiation.
  • To identify potential substrates of PKC-delta in HL60 cells.

Main Methods:

  • Indirect immunofluorescence microscopy to visualize PKC-delta and vimentin.
  • Immunoprecipitation assays to assess protein interactions and phosphorylation.
  • Treatment with TPA to induce differentiation and chelerythrine to inhibit PKC activity.

Main Results:

  • PKC-delta was found in the nucleus and cytoplasm of differentiated HL60 cells, associated with intermediate filaments.
  • PKC-delta colocalized with vimentin, a key intermediate filament protein.
  • Vimentin was phosphorylated in differentiated cells, and this phosphorylation was reduced by a PKC inhibitor, indicating vimentin is a substrate for PKC-delta.

Conclusions:

  • PKC-delta is localized to vimentin-containing structures in differentiated HL60 cells.
  • Vimentin is a direct or indirect substrate for PKC-delta.
  • PKC-delta may regulate cell shape change and adhesion during HL60 cell differentiation through vimentin phosphorylation.

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