Quantitative proteome analysis of detergent-resistant membranes identifies the differential regulation of protein kinase C isoforms in apoptotic T cells

Proteomics. 2010 Aug;10(15):2758-68. doi: 10.1002/pmic.201000164.

Abstract

Several lines of evidence suggest that detergent-resistant membranes (DRMs) (also known as lipid rafts and glycosphingolipid-enriched microdomains) may have a role in signaling pathways of apoptosis. Here, we developed a method that combines DRMs isolation and methanol/chloroform extraction with stable isotope labeling with amino acids in cell culture-based quantitative proteome analysis of DRMs from control and cisplatin-induced apoptotic Jurkat T cells. This approach enabled us to enrich proteins with a pivotal role in cell signaling of which several were found with increased or decreased amounts in DRMs upon induction of apoptosis. Specifically, we show that three isoforms of protein kinase C (PKC) are regulated differently upon apoptosis. Although PKC alpha which belongs to the group of conventional PKCs is highly up-regulated in DRMs, the levels of two novel PKCs, PKC eta and PKC theta, are significantly reduced. These alterations/differences in PKC regulation are verified by immunoblotting and confocal microscopy. In addition, a specific enrichment of PKC alpha in apoptotic blebs and buds is shown. Furthermore, we observe an increased expression of ecto-PKC alpha as a result of exposure to cisplatin using flow cytometry. Our results demonstrate that in-depth proteomic analysis of DRMs provides a tool to study differential localization and regulation of signaling molecules important in health and disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Apoptosis* / drug effects
  • Cell Fractionation
  • Cisplatin / pharmacology
  • Humans
  • Jurkat Cells
  • Membrane Microdomains / metabolism*
  • Protein Isoforms / metabolism
  • Protein Kinase C / metabolism*
  • Proteome / metabolism*
  • Proteomics / methods*
  • T-Lymphocytes / cytology*
  • T-Lymphocytes / enzymology

Substances

  • Antineoplastic Agents
  • Protein Isoforms
  • Proteome
  • Protein Kinase C
  • Cisplatin