Protein kinase C in primary astrocyte cultures: Cytoplasmic localization and translocation by a phorbol ester

J. T. Neary, L. O B Norenberg, Michael D Norenberg

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Abstract

The distribution of calcium-activated, phospholipid-dependent protein kinase (protein kinase C) in supernatant and particulate fractions of primary cultures of rat astrocytes and its transocation by a phorbol ester were studied. We observed that 91% of protein kinase C activity in astrocytes was in the supernatant fraction, as measured by lysine-rich histone phosphorylation assay. Attempts to uncover latent activity in the particulate fraction were unsuccessful. Approximately 75% of the supernatant protein kinase C activity could be translocated to the particulate fraction by prior treatment (30-60 min) of the cultures whith 100 nM 12-O-tetradecanoyl-phorbol 13-acetate (TPA), but not with 4α-phorbol, an inactive phorbol ester. Investigation of endogenous substrates for protein kinase C showed that TPA treatment brought about an increase in phosphorylation in membrane proteins and a decrease in phosphorylation of supernatant proteins. These findings indicate that the distribution of protein kinase C in astrocytes differs substantially from that in whole brain tissue, where approximately two-thirds of the protein kinase C activity is associated with the particulate fraction. Because protein kinase C is concentrated in the cytosol of astrocytes and most of this activity can be translocated to membranes, astrocytes may be particularly well-suited to respond to signals that activate phosphoinositide-linked receptors in brain.

Original languageEnglish
Pages (from-to)1179-1184
Number of pages6
JournalJournal of Neurochemistry
Volume50
Issue number4
StatePublished - Jan 1 1988

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Phorbol Esters
Astrocytes
Protein Kinase C
Phosphorylation
Tetradecanoylphorbol Acetate
Brain
Phosphatidylinositols
Histones
Protein Kinases
Lysine
Rats
Assays
Phospholipids
Membrane Proteins
Cytosol
Tissue
Calcium
Membranes
Substrates
Proteins

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Protein kinase C in primary astrocyte cultures : Cytoplasmic localization and translocation by a phorbol ester. / Neary, J. T.; Norenberg, L. O B; Norenberg, Michael D.

In: Journal of Neurochemistry, Vol. 50, No. 4, 01.01.1988, p. 1179-1184.

Research output: Contribution to journalArticle

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