Conventional protein kinase C plays a critical role in negative regulation of CD98-induced homotypic aggregation

J. Y. Cho, D. R. Katz, Keith M Skubitz, B. M. Chain

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

CD98, a heterodimeric type II transmembrane protein, is involved in many different cellular events, ranging from amino acid transport to cell-cell adhesion. Little is known about the positive and negative signalling pathways involved in these responses. Therefore, we examined the role of conventional protein kinase C (PKC) isoforms during CD98-induced intracellular signalling and homotypic aggregation of U937 cells. The CD98-induced aggregation was enhanced by the general protein kinase inhibitors GF109203X and staurosporin, and by specific PKC-α/-β peptide inhibitor 19-27, but inhibited by PKC activators such as phorbol 12-myristate 13-acetate (PMA). PMA-inhibition was reversed by PKC inhibitors recognising the ATP-binding site in PKC (e.g. staurosporin, GF109203X and Go6983). Inhibitors which bind to diacylglycerol (DAG) or Ca2+-binding sites of PKC (calphostin C and Go6967) had no effect. PMA-induced translocation of conventional PKC (cPKC) isozymes (α, β and γ), but decreased the expression of PKC-δ, which plays an important role in CD98-induced homotypic aggregation. PMA treatment also suppressed the surface level of CD98 but not CD29, CD18 and CD147, dose- and time-dependently. These data provide evidence that PMA-responsive cPKC isoforms (α, β and γ) play a key role in negative regulation of CD98 signalling and homotypic aggregation.

Original languageEnglish (US)
Pages (from-to)19-29
Number of pages11
JournalTissue Antigens
Volume75
Issue number1
DOIs
StatePublished - Jan 1 2010

Keywords

  • CD98
  • Conventional PKC
  • Homotypic aggregation
  • Negative regulation
  • PKC-δ
  • Phorbol 12-myristate 13-acetate
  • U937

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