Regulation of organelle movement in melanophores by protein kinase A (PKA), protein kinase C (PKC), and protein phosphatase 2A (PP2A)

Reilein, A. R., Tint, I. S., Peunova, N. I., Enikolopov, G. N., Gelfand, V. I. (August 1998) Regulation of organelle movement in melanophores by protein kinase A (PKA), protein kinase C (PKC), and protein phosphatase 2A (PP2A). Journal of Cell Biology, 142 (3). pp. 803-13. ISSN 0021-9525

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URL: http://www.ncbi.nlm.nih.gov/pubmed/9700167
DOI: 10.1083/jcb.142.3.803

Abstract

We used melanophores, cells specialized for regulated organelle transport, to study signaling pathways involved in the regulation of transport. We transfected immortalized Xenopus melanophores with plasmids encoding epitope-tagged inhibitors of protein phosphatases and protein kinases or control plasmids encoding inactive analogues of these inhibitors. Expression of a recombinant inhibitor of protein kinase A (PKA) results in spontaneous pigment aggregation. alpha-Melanocyte-stimulating hormone (MSH), a stimulus which increases intracellular cAMP, cannot disperse pigment in these cells. However, melanosomes in these cells can be partially dispersed by PMA, an activator of protein kinase C (PKC). When a recombinant inhibitor of PKC is expressed in melanophores, PMA-induced pigment dispersion is inhibited, but not dispersion induced by MSH. We conclude that PKA and PKC activate two different pathways for melanosome dispersion. When melanophores express the small t antigen of SV-40 virus, a specific inhibitor of protein phosphatase 2A (PP2A), aggregation is completely prevented. Conversely, overexpression of PP2A inhibits pigment dispersion by MSH. Inhibitors of protein phosphatase 1 and protein phosphatase 2B (PP2B) do not affect pigment movement. Therefore, melanosome aggregation is mediated by PP2A.

Item Type: Paper
Additional Information: 0021-9525 (Print) Journal Article Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S.
Uncontrolled Keywords: 3T3 Cells Animals Cell Aggregation Cell Line Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors/*physiology Enzyme Inhibitors/pharmacology Melanocytes/metabolism/physiology Melanophores/*physiology Mice Microtubules/physiology Organelles/*physiology Phosphoprotein Phosphatases/antagonists & inhibitors/*physiology Phosphorylation Pigments, Biological/physiology Protein Kinase C/antagonists & inhibitors/*physiology Protein Phosphatase 1 Protein Phosphatase 2 Transfection Xenopus
Subjects: organs, tissues, organelles, cell types and functions > cell types and functions > cell types > cell line
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > cell line
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > cell line

bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > transcription factor > Cyclic AMP
organs, tissues, organelles, cell types and functions > organelles, types and functions
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression > phosphorylation
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > kinase > Protein kinase C
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > protein phosphatase
Investigative techniques and equipment > transfection
organism description > animal > Frog > xenopus
CSHL Authors:
Communities: CSHL labs > Enikopolov lab
Depositing User: Kathleen Darby
Date: 10 August 1998
Date Deposited: 01 May 2014 14:59
Last Modified: 01 May 2014 14:59
PMCID: PMC2148163
Related URLs:
URI: http://repository.cshl.edu/id/eprint/29925

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