Abstract |
Differentiated neuroblastoma cells exhibit both the delayed rectifier potassium current (IK) and the M-current (IM). The present study was designed to determine the roles of protein kinase C (PKC) and of the calmodulin- binding protein 80K/MARCKS, a prominent substrate for PKC and possible regulator of these currents. Neuroblastoma x glioma (NG108-15) hybrid cells transfected with m1 muscarinic receptors were grown with 1% fetal bovine serum (FBS) without the prostaglandin E1 ( PGE1) and isobutylmethylxanthine ( IBMX) usually added in preparation for electrophysiological studies. Under these conditions, the usual pleomorphism was largely abolished, leaving two populations of small cells with stellate and spherically symmetrical geometries. Whole-cell patch clamping indicated that the two cell types had identical electrophysiological properties, displaying: IK, a small current through a "T-like" Ca2+ channel, and no M-current. Stimulation with carbachol shifted the distribution of cells to a more stellate morphology within 24 hr and later (after 48 hr) reduced the PKC substrate 80K/MARCKS by 22 +/- 7%. In contrast to the stimulation of IK observed with cardiac cells, PKC activation produced only a small inhibition of IK, which was independent of carbachol pretreatment. Thus, PKC and 80K/MARCKS can be dissociated from the regulation of IK in neuroblastoma cells.
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Authors | M M Civan, J Robbins, S Broad, E Rozengurt, D A Brown |
Journal | The Journal of membrane biology
(J Membr Biol)
Vol. 133
Issue 1
Pg. 51-9
(Apr 1993)
ISSN: 0022-2631 [Print] United States |
PMID | 8320719
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Intracellular Signaling Peptides and Proteins
- Marcks protein, mouse
- Marcks protein, rat
- Membrane Proteins
- Proteins
- Receptors, Muscarinic
- Myristoylated Alanine-Rich C Kinase Substrate
- Carbachol
- Protein Kinase C
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Topics |
- Animals
- Carbachol
(pharmacology)
- Cell Differentiation
- Down-Regulation
- Electrophysiology
- Glioma
(metabolism)
- Hybrid Cells
(metabolism)
- Intracellular Signaling Peptides and Proteins
- Membrane Proteins
- Mice
- Myristoylated Alanine-Rich C Kinase Substrate
- Neuroblastoma
(metabolism)
- Protein Kinase C
(metabolism)
- Proteins
(metabolism)
- Rats
- Receptors, Muscarinic
(metabolism)
- Substrate Specificity
- Tumor Cells, Cultured
(drug effects, metabolism, pathology)
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